A meeting between the entire Polish communist leadership and the Kremlin's chief ideologist Mikhail Suslov has underscored major -- and unresolved -- differences of approach between Moscow and Warsaw in tackling the Polish crisis, according to Western observers who analyzed an official joint communique.

But indications here are that the Polish leadership stood its ground and defended the need for change during yesterday's session. With Suslov's departure today after a surprise visit lasting less than 24 hours, the Polish political timetable continued to be dominated by preparations for reform.

Detailed negotiations with the independent Solidarity trade union are due to start Saturday and the Central Committee meets next Wednesday to discuss changes in the Communist Party statutes and the Politburo.

A close reading of the communique issued after yesterday's talks indicates that the Polish side attempted to explain to Suslov the impossibility of governing Polan in opposition to the wishes of the nation. This in turn implies that the Communist Party itself must be responsive to the opinions of its own rank-and-file.

The statement said that, in the Polish view, "the union of all patriotic forces within the nation is of great significance for averting the threat to the gains of socialism in Poland and opposing attempts to spread anarchy."

Translated from diplomatic jargon, this would appear to mean that the first priority of a Communist Party leadership in Poland must be building up national unity and trust. If the party leadership attempts to go against the wishes of the majority of Poles, the net results is to strengthen popular support for "forces hostile to socialism."

The official Polish view now is that the vigorous debate among ordinary communists can do much to restore the party's standing and reputation in the eyes of the population.

It is most unlikely that Suslov, at 78 the custodian of Soviet orthodoxy, sees the Polish crisis in the same light. For him, all developments in Poland since last summer have represented steps away from "real socialism." Seen from Moscow's angle, the recent ferment inside the Polish party has been particularly alarming.

Observers noted that there was no reference in the statement to "identity of views" or "mutual understanding" -- favorite phrases of Soviet Bloc communiques.

In another development, the Polish government postponed "for technical reasons" a trial of right-wing dissidents belonging to an organization called Confederation for an Independent Poland. It was scheduled for next week. Moreover, three dissidents have been relased over the last few days from preventive detention -- thus reducing Solidarity's list of "political prisoners" to eight.

The authorities also issued figuresd showing a total of 207,000 people had left the party since Sept. 30, 1980. Party membership is now under 3 million. An official commentary attributed the decline to "social and political tensions, economic crisis, the mood of disappointment, disillusionment, bitterness, and shattered ideas."

The commentary said 136,000 party members had resigned while 71,000 had been purged for violating the party's norms or ethnical misdeeds. It said those dismissed included a number of senior officials.