President Carter's personal agenda for the Venice economic summit conference, which ended Monday, was tailored to his own domestic political needs and had little room in it for attention to the American hostages in Iran.

That agenda called for making the Soviet Union's invasion of Afghanistan the central political topic of the talks and for a dislpay of Western "unity" on the issue.

It also meant pushing the Iranian crisis far into the background, making the 53 American hostages held in Iran nearly eight months the all-but-forgotten people of the sixth annual gathering of the leaders of the industrialized democracies.

This has been Carter's approach ever since the failure of the Iranian rescue raid in April. Throughout the winter, when the White House so successfully made the hostages the centerpiece of Carter's reelection campaign, the United States publicly appealed to its allies for help in gaining the release of the hostages.

It was said then by the administration that the hostages were not just an American problem but a matter of international concern a threat to the conduct of diplomacy.

But now it is June, and there is no real prospect that the Americans will be freed before the first anniversary of their captivity, Nov. 4, which will also be election day in the United States.

They are now a political embarrassment to the president, and so as he met with the allied leaders in the warm glow of the first days of summer in Venice, they were barely mentioned.

The seven leaders, from the United States and its prinicipal allies in Western Europe, Canada and Japan, did "vigorously condemn the taking of hostages and the seizures of diplomatic and consular premises." But they did not mention Iran by name, and when White House press secretery Jody Powell was asked about this he dismissed the question with sarcastic disdain.

"It seemed to us the reference was quite obvious," Powell said. "Anybody that can read that statement and not think about Iran is even less preceptive than some of the folks I've met."

From the beginning of the President's week-long trip to Europe, it was clear that his main objective for the Venice summit conference was for the Western alliance to appear united on the issues he deemed to be of overriding importance.

During two days in Rome prior to the summit he said repeatedly that reports of "disarray" in the alliance under his leadership were grossly exaggerated, and that the allies" public disputes over tactics were in fact a predictable and healthy sign of democracies at work.

Iran, however, was not the issue on which to stage a show of unity here.

While the other leaders may have understood why Carter made so much of the hostages throughout the winter months, they never fully approved of that approach and only reluctantly went along with a limited number of economic sanctions to put pressure on Iran.

Far more dependent on imported Middle Eastern oil than the United States, the European countries and Japan were not eager for a confrontation with Iran in Venice. Carter did not ask them to go any further in that direction.

Instead, in declarations that began as he was leaving the White House last Thursday and continued through the summit conference, Carter made Afghanistan the central issue and was rewarded with a joint declaration demanding a complete withdrawal of Soviet troops.

There are in fact important differences between the United States and some of its allies over how hard to push the Soviets on the Afghan issue. This is particularly true with the European countries, which have important trade links to Moscow and live next door to the military power of the Warsaw Pact.

But these differences were glossed over in the Venice declaration, which pledged the allies "to do everything in our power" to achieve a Soviet troop withdrawal but was devoid of any specific commitments toward that end.

For Carter, this was enough. Under fire in Europe as a weak and uncertain leader who has allowed alliance relations to deteriorate, he could least afford a failure to achieve unanimity on an issue on which he has placed so much emphasis.

American officials defended the Afghan declaration's lack of specifics, saying such matters are not the sort decided at a summit conference and suggesting that there will soon be additional allied pressure on the Soviets.

By the summit's end, Carter's satisfaction with the results was evident. American reporters were invited to his hotel, where for more than 30 minutes he answered questions in an informal setting. Like his White House aides before him, he stressed the importance of the conference's "unity" in opposing the Soviet invasion of Afghanistan.

He was asked why the conference's declaration did not specifically mention the Americans in Iran, and why he made no specific reference to them in his public statement with the other leaders at the conclusion.

Carter said he discussed the hostages privately in a series of meeings with other leaders.

"In my private discussions with the leaders, we covered, in each case, what the countries are doing to help us, either through the United Nations or through the United Nations or through diplomatic or other means," he said. o

"Some still have personnel in Iran who are giving assistance to us. So that's a matter of great concern to all of us."

Had there, he was asked, been a conscious decision not to mention the American hostages?

"No," the president replied, 'there was no conscious decision."