Reagan keeps US high-tech from Soviets - at a price.

The Reagan administration has won the latest round in its long-running battle with America's NATO allies over sale of ''strategic'' equipment to the Soviet bloc.

But the ''West-West'' war between transatlantic partners appears certain to continue for some time to come.

Bowing to United States pressure, the Belgian government announced last Thursday that sophisticated machinery made by a small Belgian company would not be sold to the Soviet Union as originally planned. US officials had said the machinery could end up in the hands of the Soviet military.

The Belgians then said the machinery would be bought by the Belgian Army. But it appears the Army can't afford the equipment.

So now the US Defense Department, according to US officials, has decided to foot nearly half the bill for the Belgian military.

This new twist in the transatlantic dispute over what the West should sell to the Soviet bloc came only hours after West German Economics Minister Martin Bangemann said his country ''would not tolerate'' new moves by the US to restrict transfers of Western technology to the Soviet bloc.

Mr. Bangemann said that, if necessary, the Bonn government would enact legislation allowing West German companies to ignore ''extraterritorial'' curbs imposed by foreign countries.

Reports from France, meanwhile, say that the French government has begun studying ways to sell highly sophisticated electronic telephone exchanges to East-bloc countries despite an agreement last month among Western nations to ban such sales until 1988. This is certain to anger Reagan administration hard-liners.

The Belgian case, resolved last week to the apparent satisfaction of both the American and Belgian governments, involves the sale of nearly $2 million worth of sophisticated machinery. The Belgian company applied for the requisite export license two years ago.

Last week a team of experts from the US State and Defense departments visited the Belgian company that manufactured the machinery and concluded that the equipment, while extremely sophisticated, was harmless in defense terms.

But the official US view continued to be that if the ''end user'' of the equipment turned out to be the Soviet military, the sale would contravene the objectives of the accord recently concluded by the Coordinating Committee for Multilateral Export Controls.

To many Europeans, that line of reasoning, carried to an extreme, could elevate tension between the US and its NATO allies on the technology-transfer issue to a very high level.

''Sure,'' said a European diplomat, ''almost anything we sell to the Russians could be used to bolster the country's military might (and its) economy in general. The lingering threat of the Americans objecting to any possible sale we might make could deal a devastating psychological, if not real, blow to our whole trade with the Eastern bloc. ''