U.S. Trade Representative William Brock said yesterday that the Warsaw Pact nations will be treated differently than the Soviets in trade matters and that, in a reversal of the stance under previous administrations, trade policy will be linked to foreign relations.

"I don't know how you can deal with people except in the totality of the situation," Brock told the Joint Economic Committee. Brock was asked by Rep. Margaret M. Heckler (R-Mass.) whether he would designate a policy on high-technology exports for the Eastern Bloc countries different from that with the Soviets.

"I would think so," Brock said. "There's no reason not to treat individual nations as individual nations. Some have been more forthcoming."

Brock's comments emphasized a new Reagan administration line that is becoming known as the Brock Doctrine, or a return to linkage between trade policy and other foreign policy considerations, a course abandoned by recent previous administrations, a government official said.

The doctrine says it is impossible to consider trade "in splendid isolation from foreign policy considerations" and that no single issue involved in bilateral negotiations can be isolated from other issues. For example, the United States can't be friendly politically, socially and diplomatically with a trading partner, but hurt it in the trade area or be unfriendly with a country and continue active trading that may aid the enemy, the official said.

As an example of the new administration's change in trade policy, just this week government representatives in Paris agreed to aid Poland by deferring the repayment of more than $80 million in official debt owed to the United States.

Brock said resumption of exporting high-technology goods to the Soviets would depend on the availability of those goods from other countries and "actions of the Soviet Union" in the total world community of which the Soviets "haven't been a responsible member."

High-technology exports to te Soviet Union were stopped last year by the Carter administration in response to the Soviet invasion of Afghanistan. tAt that time, the United States were exporting between $155 million and $180 million in high-technology items to Russia, but never stopped shipments to Soviet satellite countries. High-technology trade to Communist countries in 1979 was $493 million.

The Trade Policy Committee, which Brock heads, has made East-West trade a high-priority item, an administration official said.