In an accord hailed as a major step toward improved ites between East and West Europe, the European Economic Community and Comecon, the Communist economic bloc, agreed here to open talks early next year to foster closer economic relations.

Since initial contacts began four years ago, Comecon - made up of the Soviet Union, its East European partners and Cuba - has refused to grant full diplomatic recognition to the Common Market.

On Wednesday, Mihai Marinescu, vice premier of Romania and president of Comecon's executive committee, was received by Henri Simonet, Belgian foreign minister and acting chief of the EEC Council of Ministers. Later Marinescu met with Wilhelm Haferkamp, EEC commissioner for external affairs, a move regarded as tacit acceptance of the Common Market Commission's role as the EEC commercial spokesman.

Dominated by the Soviet Union, Comecon has studiously avoided conveying the impression that it accepts the notion of the European Community, or any unifying bloc of West European countries.

While China has been eager to approve and support the Community, Comecon has castigated the Common Market as a "capitalist creation," for American-led business interest.

Behind that facade, the underlying Soviet view remained staunchly apposed to efforts to enchance West European union.As the version of a full political union has faded in recent years, the Soviets have tried to open contacts with the Common Market through Comecon in an attempt to portray the latter as an equal counterpart.

EEC officialso, however, insist that there is no possibility of concluding any kind of agreement that places the two blocs on equal footing. Unlike the Common Market, Comecon hs no powers to make trade and aid agreements, has not formed a common customs union and does not have an independent executive like the EEC Commission.

This week's ministerial meeting between the two blocs did not result in any decision on what form their future relationship should take. Negotiators will meet later this autumn, in Moscow or Brussels, to begin that delicate exercise.

It seems clear that the Community would reject any Comecon proposal for a general trade and economic cooperation plan. The official EEC view holds that Comecon is little more than a simple secretariat linking the eastern nations.

EEC officials say they are prepared to establish ties tht would provide for information exchanges in such areas as economic and trade statistics, and environmental issues.

In the past, the Community has offered to negotiate bilateral trade pacts with Comecon's member states. Only Romania, which has signed a textiles agreement with the COmmon Market, has expressed interest in such an offer. East Germany, Poland and the Soviet Union relented early this year and decided to negotiate fishing agreements with the EEC Commission, which may here viewed as an event tantamount to diplomatic recognition of the Common Market.

Comecon appears to be seeking a broad agreement which would permit individual states in the two blocs to work out a web of bilateral trade and economic links.

Apart from its unwillingness to let the Eastern bloc believe Comecon is its equal, the EEC is wary of helping the Soviets extend control over its satellites in the domain of foreign trade, where Eastern countries have asserted relative autonomy in the past.