The decision by the shah of Iran to cancel his long-planned trip to East Germany and Romania ends his attempt to maintain a business-as-usual image despite the growing civil unrest he is facing.

The decision will cause considerable disappointment in Romania and East Germany. Like so many other countries across the world, they have remained determined to woo the shah's favors and were ready to turn a blind eye to the deep troubles besetting his monarchy.

Even though the disturbances in Iran have been bubbling for months, diplomatic activity has been carried on as if the internal situation were calm. The most illustrious guest there recently was China's Chairman Hua Kuo-Feng. To assure his security, the shah provided a helicopter for his travel between the airport and his Tehran residence. Nevertheless, the shah made it his main theme in discussions with Hua to talk of regional security in the Persian Gulf and Indian Ocean.

Hua, in turn, made it clear that China now looks to imperial Iran as part of a bulwark against the Soviet Union, including Moscow's growing influence in Afghanistan.

This week Japanese Prime Minister Takeo Fukuda was in Tehran, Fukuda was unable to attend a reception in his honor Thursday night because of the troubles.

Next week, the shah had planned one of his sallies into the communist world. The Romanian visit was intended as a return for President Nicolae Ceausescu's earlier stay in Tehran. The visit to East Germany was part of the shah's strategy of maintaining good relations with the communist bloc, an insurance policy against 25 Soviet divisions stationed within striking distance of the Iranian-Soviet border.

Although the Soviet Union and Iran are wary of each other, Moscow always has been careful to avoid polemics against the shah and has fostered economic links between the two countries. The Soviets also have encouraged other Comecon countries to trade with Iran and buy some of the oil which Moscow can no longer supply to is bloc partners.

In advance of his planned visit to East Germany, the shah last week was interviewed by the official Communist Party paper, Neues Deutschland and was addressed by the East German journalist as "imperial majesty."

The shah was asked about Iran's plans for "consolidating detente." The shah replied, "We have always been a reliable member of the U.N. . . . We believe in coexistence, not only in living in peace side by side but in cooperation between all states with different systems"

"The question between the developed and less developed countries must be settled, he added. "It is not possible to have justice when a few nations live in prosperity and happiness and others in misery."

Although the shah has long concentrated on criticizing Western industrialized nations for neglecting problems of poor nations, the West, notably the United States, has been his chief arms supplier and supporter. In return, Iran has supplied oil to Israel and South Africa, which would otherwise have had great difficulties in meeting all their requirements.