The "temporary" movie theater and visitors center beside the Washignton Monument, built's as a Bicentennial gift by the Eastman Kodak Co. for close to $1.5 million, will be temporary after all.

Due to be razed fall after Bicentennial crowds had departed, the 300-seat theater was giben an additional six-month lease on life while the National Park Service considered other possibel used for it.

But the theater's doom apparently was sealed last week, and its demolition set for May 1, despite Senate interest in it and a last-minute appeal from the White House to the House committee that contorls Park Service purse strings and actually is making the final decision on the building.

The White House two weeks ago asked Rep. Sidney R. Yates (D-Ill.), chairman of the House APpropriations subcommittee on Interior and Related Affairs to postpone demolition at least another 90 days. The theater was being considered for use by tourists this summer and as part of the President's "people program," which may bring citizen from around the country to Washington, according to Greg Schneiders, director of White House projects.

The Park Service last summer proposed keeping the theater as a "temporary? visitors center until a permaently underground facility proposed in the 1966 plan for the Washington Monument grounds is build or has proposed using the small theater to show films on the nation's capitol. The popular 14-minute film "Washington the Man" was seen in the theater last summer by more than 300,000 visitors.

Yates is able to exercise a veto over continued use of the building following a joint House-Senate conference last summer which agreed both Interior and Related Affairs subcommittees must approve any future use of the building by the National Park Service.

Yates's subcommittee stated in a report last June it was concerned about the proliferation of temporary buildings on the Mall . . . and expects all such buildings to be removed at the end of the Bicentennial."

The companion report of the Senate subcommittee said "it shares the concern (of the House subcommittee but feels the small theater) serves a useful and popular role and doesn't appear to intrude on the general Mall environment." A spokesman for the Senate committee said this week "we fell the building should be kept . . . it's in a hollow and not as noticeable as the snack bar and tourist building already there. But it's Mr. Yates's decision. He has a veto power."

The last "temporary" buildings on the Mall, the Navy and Munitions Buildings located on what is now Constitution Gardens, were built in 1917 and lasted more than 50 years.

The apparent final decision to demoish the theater was made during budget hearings by Yates's committee last week, in a conference telephone call among Yates, Park Service Director Gary Everhardt, director of National Capital Region parks Jack Fish and chairman of the federal Fine Art Commission (and National Gallery director) J. Carter Brown.

It apparently was a "consensus" that there was no overwhelming need for the building, that it would take at least two months to get the Fine Arts Commission's blessing to keep the building on the Mall - since its original approval was for the Bicentennial year only - and that it should be torn down, said a spokesman for Yates.

Yates then wrote a note to Schneides at the White House to let him know how - the drama of the little theater was ending. "He didn't deny my request for a 90-day extension," said Schneiders, but wrote that the Park Service had reversed itself and there are now "a consensus that the building should be torn down. I'm not that interested in trying to reverse a consensus and it's my inclination to let those who have a much greater interest in the theater do what they will with it," Schneiders said.

He said it wasn't really a case of the White House and its Park Service "getting their signals crossed," but just that "I wanted to add my voice to others" who had expressed interest in possibly keeping the theater for another year or two.

The Park Service said this week that a number of groups, such as the Daughters of the American Revolution, and many individuals have called and written asking that the theater and its film on Washington be continued for at least another tourist season.

"We know we have to improve the lot of the visitor to the Washington Monument," says Leroy (Whitey) Rowell, special assistant to local parks director Jack Fish. "We don't host visitors there in a pleasant manner the way we do at the Lincoln and Jefferson Memorials.

They just go and stand in a line . . . and the theater could help change that. We don't want to keep the building. It's not the right building in the right place. But why throw it away? Of course the deal was to take it down after a year and if that's Congress wants that's what we'll do," Rowen said.

One of the building's staunchest defenders is an Oakton, Virginia, woman, Mrs. George Yeomans, who only visited it once but loved the film on Washington and has been telephoning Yates and every member of his committee as well as Fish, Rowell, Everhardt and anybody else who'll listen.

"I'm a Canadian by birth and I just happened to go down and see the show," says Yeomans, "and then I heard they were going to tear down the building. It seemed like such a waste of money. They should keep it at least until there's something better.

"But what I especially liked was that they finally had something about George Washington at his monument," said Yeomans. "Before there was nothing."

The Eastman Kodak Co., which maintained, staffed and promised to raze the building, last week issued a statement saying only that it had postponed demolition last fall at the request of the Park Service while "governmental authorities determined (whether to use it) during the 1977 season."

Schneiders at the White House said that while he now considers the issue as pretty much closed, "I will check again with Yates and see what the situation is and what they want to do."