In a policy decision speeded by the Soviet invasion of Afghanistan, the Pentagon yesterday made clear it is willing to sell certain kinds of military equipment -- but not weapons -- to China.

The announcement, coming on the heels of a strong challenge Wednesday to Soviet actions by President Carter in his State of the Union address to Congress, seemed clearly to be another step in exerting pressure on the Kremlin from all sides.

The Defense Department cited trucks, communications equipment and early warning radars -- the kind that can be used to detect invading aircraft or tanks -- as the type of equiopment that might be sold.

Trucks and communications equipment, on the surface, appear neither controversial nor glamorous. Yet they could play a key role in modernizing and adding maneuverability to a huge Chinese Army that frequently is hampered by primitive transportation and inability to communicate among units.

Earlier this month, Defense Secretary Harold Brown visited Peking and said the United State was willing, on a case-by-case basis, to consider selling certain high-technology items -- such as computers -- to China that were primarily commercial but could have some military use.

In making it clear yesterday that they were now, in fact, displaying a greater willingness to sell equipment with more direct military uses, Pentagon officials described it as an "incremental step" in broadening ties between the two countries.

The announcement and briefing for reporters suggest the adminstration is intent on calling attention to its decision and giving the Soviets pause, as one senior government official said.

The announcement, however, also gave pause to Rep. Lester L. Wolff (D-N.Y.), chairman of the Asian and Pacific affairs subcommittee of the House Foreign Affairs Committee.

Wolff described the move as "a great departure from previous relations with China and said, "I strongly oppose this idea until such time as we know what we are going to get in return from the People's Republic of China."

Brown had gone to Capitol Hill Wednesday to discuss the forthcoming announcement with various committee chairmen.

Officials said the plan evolved before Brown's trip and before the Soviet thrust into Afghanistan but that the Russian move hastened a decision that would have to have been made anyway.

Officials indicated privately that sales of such equipment were the logical thing to do if ties were to be normalized and that the policy probably would be reviewed in about a year to see if further steps are justified.

Yesterday, however, the Pentagon continued to stress that its position of not selling weapons to China had not changed.

Pentagon officials claimed no specific requests has been received from the Chinese nor had the Defense Department made decisions on specifically what equipment would be offered for sale.

Pentagon officials said the equipment could be sold from U.S. military stockpiles or ordered from American firms, and they did not rule out the possibility that American technicians might be sent to China to help train Chinese counterparts.