With several hundred singing, chanting students marching outside in a noisy candlelight vigil, parents and graduates of Immaculata Preparatory School jammed its gymnasium last night to protest the planned closing of the 69-year-old school.

More than 25 speakers, backed by an audience of more than 600 persons, accused the Sisters of Providence, the Catholic order that owns the school, of deserting them and placing the care of elderly nuns above the education of children.

"The bottom line appears to be the dollar," declared Elaine Walter, mother of an Immaculata student. "Is it possible that there is no place in the American Catholic Church for the education of children whose parents can afford it or will sacrifice for a quality education?"

"I am appalled that neither the parents nor the community was asked to provide any assistance when you made this decision," Joyce Young, another parent, told leaders of the Catholic order of nuns seated on a small stage. "What has happened this week has come across as an act of contempt . . . . Tell us, maybe it is not too late?"

Sister Ann Doherty, superior general of the order, replied that the decision to sell had "caused us much pain and anguish," but she said the order would "not break our word" to sell the 8.2 acre campus to American University.

Although plans to sell the property at Tenley Circle NW were disclosed only Tuesday, Sister Ann said the order had signed a binding letter of intent to do so late last year. She said the sale had been approved in June by Archbishop William A. Hickey, head of the Washington Archdiocese, and shortly afterward by the Vatican.

The property, occupied by Immaculata Prep, a high school, and Immaculata Dunblane, a grammar school and junior high, will be sold for $7.6 million. The two schools, which together enroll about 560 students, all girls, will close in June 1986. Settlement and transfer of the property, at Wisconsin and Nebraska avenues NW, will take place shortly after that.

Sister Ann said the sale was needed to raise funds for the order's aging members, more than a third of whom are over 70 years old. Many speakers said last night, however, they believed it would be much better to raise funds from Catholics to care for the elderly nuns rather than to sell a school. Several offered to make substantial donations themselves and to mount a fund-raising effort.

As the audience cheered loudly, one speaker complained that the price to be paid by American University was "the biggest robbery since Jesse James."

The city appraisal of the land, one block from a new Metro subway station, is $8.2 million, but Sister Ann said it carries a covenant perpetually restricting it to educational or religious use.

When Sister Ann told him that American University has put up just $210,000 in earnest money so far and has not yet signed a contract, many in the audience shouted that the nuns should try to cancel the sale.

Outside the gym, girls in Immaculata uniforms marched holding candles, carrying rosary beads and intermittently cheering, singing, praying and crying.

One group sang repeatedly: "High school, my only high school; you make me happy when times are blue; high school, I only love you, they're taking my high school away."

High school juniors and seniors will be allowed to complete their secondary educations at the prep schools, and students in the seventh and eighth grades will be allowed to remain until the schools close. Others must transfer next fall.

"We're the best academic girls school in Washington," said sophomore Lisa Afanasieff, 15. "And we're angry because our class, the 10th grade, won't graduate . . . Oh, some students, maybe 20 out of our class of 120 can take an accelerated course. But the average students won't graduate."

"We're also upset because of the way we learned about this. They didn't tell us. We heard it from students at other schools," said Sheila Glackin, 17, the senior class president.

"One girl heard about it at a volley ball game. From the other team. They said in assembley that the reason they hadn't told us was they had had a bad experience when they told students in another school they closed," said Glackin.

The meeting inside the gym started with a low-key description by the principals of Immaculata Prep and Immaculata Dunblane of plans for phasing out the schools over the next two years and making arrangements for students to transfer elsewhere.

But it was soon transformed into an angry protest as members of the audience lined up at a microphone on the gym floor to ask questions and to denounce the impending sale.

Archbishop Hickey was the target of several strong denunciations for approving the sale after Sister Ann disclosed that a similar effort by the order to sell a school in Chicago was blocked several years ago by the late Cardinal John Cody.

She said, however, that over the past decade seven other schools owned by the order had been sold with approval of various bishops around the country.

"Why can't Hickey be man enough and tell the pope he made a mistake in approving the sale ?" one man in the audience shouted.

Monsignor Raymond Boland, chancellor of the Washington Archdiocese, said Hickey had approved the sale because the order was in "great need." "For 80 years, they have poured their resources and themselves into this school," Boland said.

"But now, because of the Catholic ethos of our time, they are not being joined by other sisters," Boland said. "You are very sad, so are all of us . . . . We may be seeing their demise. We are seeing the end of a Catholic order. I do not know of one Catholic school that may not come to the brink of this kind of extinction."

Boland said the archdiocese would help parents who wanted to establish a new Catholic school to carry on Immaculata's program. Several speakers said they might help such an effort. But other shouted: "You can only have this school here," and "Let's keep it open."