Washington — The Reagan administration, insisting it does have a Mideast policy, has begun to disclose where it is headed in that volatile region. With a nod of approval toward a Saudi plan calling for a Palestinian state and the right of all countries in the area to live in peace, President Reagan says:
''There are aspects in the eight-point proposal made by (Saudi) Crown Prince Fahd by which we are encouraged.''
The Saudi plan, says Mr. Reagan, ''recognizes Israel as a nation to be negotiated with.'' Israel has rejected the proposal, however, saying that the document does not spell out diplomatic recognition for Israel by the Saudis.
The Saudi plan was first proposed last August and only now is being given open praise by the President.
Meanwhile, a senior administration official, speaking in a background session with reporters, said that Prince Fahd's eight-step proposal has not been put forth as a ''take it or leave it proposal.'' The senior official said that, as he understood it, the Fahd proposal was only ''a series of suggestions and ideas . . . put out for consideration.''
''We have described it as a very interesting set of proposals,'' the official went on. ''In the one instance, we are encouraged by the fact that (UN Security Council Resolution) 242 recognition of Israel's right to exist is implicit.''
Echoing the President's remarks, given earlier in an interview, the senior official had this to say when asked if the United States really does have a Mideast plan:
''Yes, I have a general framework and a direction and we think that we know where we are going.''
But this official wanted to make it clear that the US is walking on eggs in its new efforts to bring about stability in the Mideast.
''I hope,'' he said, ''we will be prudent enough to recognize that you are always confronted with unexpected surprises just as Lebanon was. You know, we were really moments away from conflict in Lebanon twice this past spring, and we shouldn't kid ourselves about that -- moments away.''
He added that these ''unexpected surprises'' can ''happen at any moment in that cauldron over there.''
Emphasizing his concern over Lebanon, this official then said: ''I get up every morning wondering and praying that something has not blown . . . . It is just inherently fragile and the Syrian demeanor is going to be important and the Soviet demeanor is going to be extremely important.''
Regarding the emphasis the President now is giving to formulating a US plan on the Mideast, the senior official said:
''I notice a great deal of attention in recent days to the so-called eight points. I want to emphasize with the greatest clarity that the United States is committed to the Camp David process and the Camp David agreement. That is America's policy at this juncture in our Middle Eastern game plan.
''I would like to say a word about that because . . . I hear everyone saying, 'We haven't got a Middle Eastern policy, we haven't got a Middle Eastern policy.' If we keep saying it, we may convince ourselves, but it will not be the truth. We have a Middle Eastern policy.''
''When we came in January, the talks associated with the withdrawal of Israel from the Sinai were totally stalled. There were intractable differences between Israel and Egypt on the composition of any kind of a force, with Israel insisting that it must be all American and with the Egyptians insisting that no Americans would be accepted.
''We have bridged those gaps. We began to bridge them in April, during our visit there. They have since been completely bridged. We have found the unique situation where our European partners, not for reasons that are necessarily shared in Washington, but for other reasons, in a post-Sadat world, have now developed an increasing level of enthusiasm to join the peace-keeping forces in the Sinai.
''That includes such nations as Italy, France, the Netherlands, Belgium, and Great Britain. Now whether that will all take place within the next few days we will have a better answer.
''So I would say that the Sinai withdrawal looks like it will occur on schedule, and it has been the product of a Middle East peace policy.''
On United States moves related to the question of autonomy, the senior official had this to say:
''In January we were confronted with an even more severe stalemate on the question of autonomy. We had a situation where most talks not only stalled out on the substantive differences between the parties, but became victimized somewhat by the domestic politics of two of the partners in that process, the United States and Israel.
''Now in the subsequent months, as a result of our actions and the substantive judgments, subjective judgments of the parties, those talks look somewhat more promising . . . .
''We intend to be a full partner in that process and at the appropriate time, if it will make a constructive contribution to that process, we would raise the level of the American participation in those autonomy talks.''