China and Italy signed a defense cooperation agreement today that could lead to significant Chinese purchases of Italian military equipment and technology.

During a visit to Peking by Italian Defense Minister Giovanni Spadolini, the two sides were reported to have discussed a wide range of possible weapons purchases, with the greatest emphasis on enhancing China's defense technology. But Spadolini said there was no discussion of the quantities of Italian weapons to be sold, and the Chinese apparently did not commit themselves to any firm purchases.

The Sino-Italian defense agreement appeared to be the first of its kind to be concluded between China and a western country. But some veteran observers here expressed caution, noting that the Chinese have a long history of showing an interest in certain arms purchases from western nations and then backing off. Actual weapons purchases from the West have been limited largely to the licensed production here of British aircraft engines and the acquisition of a relatively small number of helicopters and armored vehicles.

n addition to arms sales, the Chinese-Italian agreement would call for the training by Italy of an undetermined number of Chinese military personnel, particularly in technological fields.

Gen. Pietro Giannattaso, Spadolini's Cabinet chief, told a reporter that the Chinese were particularly interested in "electronics, signals communications , and motorization."

Called a "framework agreement," the accord between the two nations was signed at noon today by Spadolini and Chinese Defense Minister Zhang Aiping at a guest house called the Courtyard of Mutual Pleasure.

Although China, with nearly 4 million soldiers, has the largest Army in the world, the gap between its military technology and that of the Soviet Union has been widening for some years. China's leaders gave the military the lowest priority when they launched their "four modernizations" program several years ago.

But China's February 1979 invasion of Vietnam revealed weaknesses in the Chinese armed forces, including mechanical failures of armored vehicles and a lack of adequate communications and logistical support.

Because of their independent foreign policy posture, the Chinese apparently are wary of remedying their military problems by forming too many open links with the American military. To go to Italy and other Western European nations for military assistance and arms purchases is a less controversial way for the Chinese to proceed, some observers say, particularly when it comes to Chinese sensitivity to Third World views of its foreign policy.

At a Saturday press conference, Spadolini said that Italy would press for a lifting of the ban on the sale of certain defense items to China at a meeting in Rome next June of the Coordinating Committee for Multilateral Export Controls, or Cocom. The Paris-based organization, made up of NATO members and Japan, controls the flow of strategic products to communist nations.