John E. Jacob, president of the National Urban League, is deeply worried by the new Reagan budget.
''It is anti-poor, anti-disadvantaged, anti-cities,'' he says. In his eyes, the Reagan administration's emphasis on ''new federalism'' and ''self-help'' masks a dangerous change for the federal government: abandonment of its role as the the ''protector of human rights.''
At a time when ''so many, many social programs'' face elimination or trimming , Mr. Jacob lists these issues as priorities for the -Urban League:
* Employment: ''Obviously, jobs are vital to black people -- 22 percent unemployed; nearly 50 percent youth unemployment,'' he says. Households headed by women ''are black people's largest poverty-stricken group.''
* Black teen-age pregnancy: Young black women are ''babies having babies.'' ''The issue is not simply a question of morality; it is one of perpetuating problems of poverty.''
* Crime by blacks against blacks: ''Crime in our communities has stagnated development. We can't get businesses to invest. . . . And neighborhood enterprises are not willing to expand.''
* Voter education and registration: Poor and minority Americans have a record of not voting. The league supports extension of the Voting Rights Act of 1965.
Jacob now is on a speaking tour that will take him to 36 cities before the end of May. The trip, he says, is to ''seek a creative partnership among the Urban League and other volunteer service agencies, the private sector, and the public sector.''
Speaking to a Boston audience that included financial and business executives , Jacob challenged private enterprise to take the lead in addressing problems of the poor and disadvantaged.
''President Reagan has the notion that the private sector can and ought to fill the void made by government cuts,'' the civil-rights leader says. ''I disagree. We know that the private sector cannot fill the gap, but the private sector can take responsibility for playing a strong role in solving problems.''
To private industry he suggests: ''Be honest. The private sector has not done enough to face issues of the poor. The private sector can aggressively speak out for the poor, for the cities, for the disadvantaged. It can demand that government live up to its obligations.
''The National Urban League has not written off Mr. Reagan,'' he adds. ''Our charge is to offer ourselves to the President to help him serve the nation's needs. We would like to see his recovery plan work, but the poor cannot wait. . . .
''The 1980s appear to be bleak for black people, but the National Urban League has a mission to fulfill, regardless of the Reagan administration, regardless of a financial crunch,'' Jacob says.