Thousands of dollars from Iranian and American businessmen are being poured into a massive show of public support planned for shah of Iran to offset protest demonstrations by militant Iranian students when the shah arrives here Tuesday for a state visit.

More than 400 Iranian armed forces personnel undergoing routine training at Lackland Air Force Base in San Antonio, Tex, are scheduled to be flown here as civilians to help swell a crowd expected to be in the thousands. It was learned.

Coordinators for large Assyrian, Armenian and other Iranian-related ethnic groups in Chicago and Los Angeles acknowledge that private business money is being contributed to help pay for plane fares and hotel accommodations for the pro-shah demonstrators.

But they denied accusations by the Iranian Students Association that the Iranian government also is bankrolling the effort.

One organizer estimated that about 1,000 lower income ethnics will be given an average of $150 each to pay their way to Washington for the shah's two-day visit. The other will pay their own way, the organizer said.

An Iranian embassy spokesman here said he was unaware of the scheduled flight of 422 Iranian military personnel from Texas, but added, "I would suspect they are paying their own way."

Doug Moore, an information officer for the U.S. Air Training Command at Randloph Air Force Base in San Antonio, confirmed that 422 of 464 Iranian military personnel at nearby Lackland Air Force Base are set to fly to Washington for the shah's visit. He said he did not know who is paying the cost, "but it is not an U.S. expense."

Moore said the Iranians at Lackland like more than 1,000 other scattered at various military installations in the United States are undergoing routine training under a military aid agreement with Iran.

The shah's visit comes amid some of the most intense preparations for street demonstrations here since the days of the Vietnam antiwar movements. Pro- and anti-shah forces are working feverishly to neutralize and discredit each other with competing mass shows of strength.

The efforts include a mad scramble for choice demonstrations spots near the White House and cross-accusations that each faction is financed by outside powers.

D.C. police, Secret Service and other law enforcement agencies are girding for two days of demonstrations starting Tuesday with elaborate plans to keep the competing groups separated from each other and well removed from the shah and his encourage.

Authorities say they expect between 5,000 to 9,000 demonstrators from each faction.

In the blitz of accusations and counter-accusations, leaders of the pro-shah groups contend that the Iranian students are Communist-dominated.

Iranian government sources say that Cuban intelligence organizations have financed and trained underground revolutionary groups in Iran and that many elements of the Iranian Students Association here are above-ground manifestations of the revolutionary movement in Iran. Numerous weapons seized in Iran have been of Cuban manufacture, according to the government sources.

Student association leaders deny the changes, contending their organization is ideologically unaligned and is merely opposed to the shah's regime which they consider repressive.

"The individual members are a mixture of Moslems, socialists, democrats, Marxists, but the organization is united only in its opposition to the shah," said one member who, like most others, asked to remain anonymous.

Many members say they fear reprisals by SAVAK, the Iranian secret police, if they are identified.

The pro-shah demonstrations are being coordinated primarily by the Chicago-based Assyrian-American Civic Association and the Kach Nazar Armenian Organization of Los Angeles.

Atour Odisho an Assyrian organizer and president of a Chicago travel agency handling some of the charter flight service, estimaged that 5,000 demonstrators "from nine Assyrian-American Association of Chicago, said, "Some people are paying their own way and some people (are paying) by the donations of Assyrian businessmen . . . including same wealthy Assyrians from Iran."

He said an organization called the Assyrian Universal Alliance is responsible for coordinating donations of money by American and Iranian businessmen.

The Assyrian Universal Alliance is a little-known organization headquartered in Hartford, Conn., in the home of its president, William G. Yonan. Another of its officials, Sam Andrews, reportedly returned recently from a trip to Iran as part of the Alliance effort to coordinate private donations to the pro-shah demonstrations.

Assyrian and Armenian-Americans maintain some affinity with Iran where there are small Assyrian and Armenian Christian minority enclaves in that predominantly Moslem country.

"We have a moral reason to support the shah," said Mike Minassian, a coordinator of the Armenian Solidarity Friendship Committee of Los Angeles. "Iran is a Moslem country, and we (Christians) are comparatively free there . . . We have no beef with the shah."

Odisho said the shah recently had liberalized restrictions on use of the Assyrian language in Iran, "and so we want to show our support of him for that."

Homer Ashourian, an Assyrian member of the Majlis, or lower house of the Iranian parliament, toured the United States last September, lauding the shah's new policy on the Assyrian language. Similarly, Mar-Dinkha, Patriarch of the Assyrian Church of the East, toured Assyrian communities here in September.

But Odisho and other organizers say neither trip had anything to do with paving the way for the shah's upcoming visit and occurred well before the shah's visit and occurred well before the shah's visit was publicly announced in mid-October.

Aprim Koshade, a partner in Idisho's Chicago travel agency, estimated that 200 demonstrators in Chicago "and maybe 1,000 nationwide" would have their charger plane fares and hotel accommodations in Washington paid for by private business donations. He siad the donations would average about $150 each.

The shah and his wife, Farah, are scheduled to arrive here from Williamsburg Tuesday, landing by helicopter either on the Ellipse or at the eastern end of the Reflecting Pool near 17th Street, according to law enforcement officials. They will stay overnight at Blair House across Pennsylvania Avenue from the White House and leave Wednesday.

Under an agreement worked out by National Park Service and other government officials, the pro-shah demonstrators will be allowed priority spots on the central portion of the Ellipse and the sidewalk in front of the White House Tuesday with the anti-shah demonstrators at more distant locations in Lafayette Park and the eastern preiphery of the Ellipse.

The positions generally will be versed Wednesday when the shah leaves, giving the anti-shah demonstrators priority locations.