Former U.S. attorney general Ramsey Clark, who defied the U.S. government by traveling to Iran last week in an attempt to help resolve the hostage crisis, left here today with no results to show for his efforts and amid Iranian charges that he is a CIA agent.

Clark's trip to Tehran to attend a conference on alleged U.S. interference in Iranian affairs, appears to have alienated most parties to the seven-month-old crisis.

On one hand, Clark returns to the United States with the possibility of being prosecuted for having violated the U.S. ban on travel to Iran. At the same time, despite Clark's friendilness to the Iranian revolution, he was made to feel unwelcome by Iran's top officials, who refused to meet with him after he was attacked by Tehran radio as being a CIA spy.

Clark arrived here bearing what he though were special credentials. He was one of the earliest most influential American supporters of the Iranian revolution. He marched against the shah in the streets of Tehran while the devoted ruler was still in power and he was though to be Iran's choice last year for American amassador to the revolutionary government here.

Yet, in the current conspiracy-minded atmosphere of Tehran, Clark's credentials were immediately tarnished by the charges made against him. Observers here believe that the widely circulated allegations against him have made him persona non grata in Iranian eyes. Iranians who had been his friends indicated they were afraid to meet him for fear that they too would be branded with the CIA label.

Clark and the nine other Americans who came to the conference also found themselves isolated at the Hilton Hotel, far from the center of Tehran, and were unable to move freely around the city.

Clark, along with five other members of the American delegation, stayed two days beyond the end of the conference in hopes on seeing a wider slice of Iranian life. But after spending most of Saturday in the hotel lobby, one of the Americans conceded, "For all we did today, we could have gone home earlier."

The cool reception given Clark and the rest of the Americans is seen by observers as providing an object lesson on Iran's revolutionary politics.

While the Americans were welcomed by the conference's sponsers, Iranian President Abol Hassan Bani-Sadr and Foreign Minister Sadegh Ghotbzadeh, the Americans' presence was considered antirevolutionary by many of the hard-line clerics who dominate the Islamic Republican Party which controls the parliament.

Tehran Radio, which is under the Islamic Republican Party's direction, used tortuous logic to compare Clark to Rudolf Hess, a high Nazi official who flew to England in the early days of World War II on a personal mission to seek peace. Despite U.S. government protests over Clark's mission, the radio commentary cast Clark's mission in the same light calling him, "the vilest agent of them all."

At Friday prayers this week, the Clark trip was derided by the mullahs as being of no importance because "everyone knows Clark is a CIA agent."

This damning criticism for the clergy, according to some observers, seems to hve prevented the contact the Americans wanted to have with government officials and the student militants who have held 53 Americans hostage since the U.S. Embassy here was seized Nov. 4.

Like all the other delegations to the conference, the Americans held a public meeting with Bani-Sadr. But according to members of the delegation, Clark wanted a second, private meeting to go over proposals that the Iranian president had made that could lead to the release of the hostages.

Clark had wanted written clarification of Bani-Sadr's proposals, which included establishment of a commission in the United States to investigate Iran's charges against America. Sources in the American delegation said that the meeting never took place.

There was also no meeting between Clark and Ayatollah Ruhollah Khomeini. Clark had last seen Khomeini in Paris before Iran's venerated religious leader made his triumphal, return here in February 1979. Nor did Clark meet with Ayotallah Mohammed Beheshti, leader of the Islamic Republican Party who is emerging as Bani-Sadr's chief rival for power here.

In keeping with the clerics' view that American agents are everywhere, six men elected to the new parliament were denied their seats Saturday because documents found in the U.S. Embassy allegedly showed them to be CIA agents.

One man, Khosrow Rigi, was accused of having lived in the United States for 23 years and of having two American wives. Khosrow Qashqai, a leader of the Qashqai tribe in southern Iran, was also denied his seat.