U.S. Trade Representative William E. Brock said yesterday the Reagan administration is reviewing high technology trade with the Soviet Union and other Communist countries and will be watching for a signal from them during the 26th Congress of the Soviet Communist Party meeting this week.

"The sense of this administration is that the Soviet Union has not been forthcoming as a responsible participant" in the world community, Brock told a press conference.

Brock said he didn't know when any decision regarding trade with the Communists would be reached. "We'll deal with these matters in stages," Brock said. "We are very aware of the present meeting" of the Communist party in Moscow, "and we'll be looking for a sign in their direction."

An adminstration official said later that the Trade Policy Committee has made a review of East-West trade, particularly the high technology aspects, a high priority item. Brock chairs the committee.

As its first meeting several days ago, the committee directed the Commerce Department to develop a study of export controls as they relate to high technology. The committee is also awaiting the results of a study on high technology sales to Eastern bloc countries, which was contracted by the Carter administration, officials said. The Trade Policy Committee will then use those results to formulate a new policy on East-West trade, administration sources said.

Brock also noted increasing difficulty in trade relations between the U.S. and Canada. The Canadian government recently announced a plan to take over foreign ownership of its oil industry. "Those problems can be resolved by getting together," Brock said. "If they want access to the freest, open market in the world, we expect quid pro quo access to their markets."

When Brock was asked if that thinking applies to investment policy, he replied, "Of course it does." Canada is the biggest trading partner of the U.S. High technology exports to the Soviet Union were stopped last year by the Carter administration in response to the Soviet invasion of Afghanistan. At that time the U.S. was exporting between $155 million and $180 million in high technology to the U.S.S.R., but never stopped shipments to Soviet satellite countries, according to the Commerce Department. High technology trade to Communist countries in 1979 was $493 million, Commerce said.

The Carter administration also imposed a grain embargo against the Soviets, which was extended by Carter before leaving office.

At the same press conference, Agriculture Secretary John Block was asked how much faster agricultural exports would grow if the grain embargo were lifted. Block said he didn't know since the Soviets "seem able to import nearly what they wanted." He added that he doesn't know whether the Soviets would even ask to buy grain if the embargo were lifted. "They may not even come to us," Block said. "My opinion is they would be coming to us to buy some feed grains and processed products."

Block, Brock, Transportation Secretary Drew Lewis and Office of Management and Budget director David Stockman held the first of five press conferences to explain and show support for President Reagan's tax and budget cutting proposals. In the trade area, Brock said that his office wouldn't be cut much and added later that any cuts would probably result in less travel by his staff.