Boston — Black Americans cannot afford four years of apathy during President Reagan's second term, say black leaders as they assess the postelection political scene. ''We need good followship and leadership,'' says M. Carl Holman, president of the National Urban Coalition. ''Some people like to find scapegoats. Younger people are coming up. They will not stand for inequities, vetoes of job bills, neglect of the needs of youth. We have to work on where we go from here. We must seek bipartisan civil rights support. Significant races are coming up in 1986 and 1988. We must get back to political work now.''
During the next four years more blacks appear ready to seek more political power through a variety of actions. These include:
* Field a national major-party candidate for president in 1988. Some of the names being mentioned include former Atlanta Mayor Maynard Jackson, Atlanta's current mayor and former UN Ambassador Andrew Young, and the Rev. Jesse Jackson.
Regarding any plans for seeking the Democratic Party's presidential nomination in 1988, the Rev. Mr. Jackson says, ''I have not made a judgment on this issue yet; but I will leave this option open.'' He made the comments in a television special, ''Jesse Jackson on the Record,'' to be aired Dec. 7, 8, and 9 on Boston's WNEV.
* Switch to the Republican Party. At best, this is expected to occur in small steps. President Reagan's share of the black vote grew from 6 percent in 1980 to 10 percent in 1984. But in comparing the number of blacks voting for Reagan with the President's total Republican vote, blacks accounted for only 2 percent of that total.
''I see a gradual change to the GOP,'' says LeGree Daniels, recently reelected chairman of the National Black Republican council in St. Louis. ''We have greater access to the Republican Party. The national party agenda includes organization of blacks and running blacks for local office. This will be a slow process, but it's a challenge we accept.''
* Organize at grass-roots levels by getting blacks more involved in local political organizations and by running more blacks for local office. This would give national candidates local, experienced cadres upon which they could build their campaigns. For example, in the TV interview Mr. Jackson says he plans ''to build a true rainbow coalition, a national progressive organization centered on 60 congressional districts I won (during the Democratic presidential primaries).
* Recruit more blacks to register, vote, and run for office from both parties. Criticism of some of the more popular black leaders during the Democratic Convention may indicate a desire for new leaders and fresh personalities, such as Mayor W. Wilson Goode of Philadelphia. The two major civil rights organizations, the National Association for the Advancement of Colored People and the National Urban League, are committed to conducting voter-registration drives in preparation for the 1986 US House elections.
In addition, the Black Leadership Round Table - a federation of more than 150 national black organizations - is planning a national conference on how blacks may become a two-party constituency in the American political mainstream. A date is to be set.
Meanwhile, blacks made no significant gains in the Nov. 6 election, says Catherine Iino, director of publications at the Joint Center for Political Studies, a black political think tank that tabulated postelection results of black voting trends.
''Robert Clark lost his bid to become Mississippi's first black congressman since Reconstruction. There was no increase in the number of blacks elected to state legislatures. Blacks cast only 10 percent of their votes for President Ronald Reagan, but their candidate, Walter F. Mondale, lost,'' she says.
''Most black elected officials were tied to supporting the Mondale-Ferraro ticket, the third-straight presidential election in which blacks cast at least 90 percent of their votes for the Democrats' candidate.''
Mr. Clark's defeat in Mississippi symbolizes black frustration at the polls: This was his second consecutive loss in a bid for Congress from a district that for both elections had a black majority.
As a result Congress will have only 20 black members, one less than the current 21 (including a delegate from the District of Columbia). Rep. Katie Hall of (D) of Ind., was unseated last spring in the primary.
Most blacks are expected to remain in the Democratic Party, but election results indicate a polarization of the races, says Thomas E. Cavanagh, research officer of the Joint Center for Political Studies. He says that black votes provided the margin of victory for three candidates for the US Senate: newly elected Paul Simon of Illinois; Howell Heflin of Alabama; and Carl Levin of Michigan, all Democrats. In Mississippi blacks gave former Gov. William Winter 81 percent of their votes, but he lost to Republican incumbent Thad Cochran.
''White voters cast only 32 percent of their votes for Mondale,'' Mr. Cavanagh says. ''The Democratic Party appears to be minorities - blacks, Jews, Hispanics, labor. . . . In Mississippi Clark received few white votes. Blacks have to attract more nonblack votes.''
''The reality of our dilemma is racism, not only here in Mississippi, but throughout the nation,'' says Joseph Delaney, head of the Oxford-Lafayette County NAACP. ''White people voted for Reagan. Black people and other minorities , especially Jews and Hispanics, remained loyal to the Democrats.''
Warren Miller, a political science professor at Arizona State University, says polarization is not new in presidential politics. Since 1960, he says, blacks have voted strongly Democratic, but whites have given a majority vote to Republican presidential candidates. Whites have voted Democratic for Congress, he adds.
''The Civil Rights Act of 1964, the Voting Rights Act of 1965, the New Deal, the Fair Deal, the New Frontier, and the Great Society legitimatized black identity with the Democratic Party since the days of President (Franklin D.) Roosevelt,'' Dr. Warren says. ''The Mondale defeat appears to be the end of a legacy. Blacks will have to look away from the past to new leadership, to new directions.''