A Washington school administrator has threatened to seek legal counsel if a 17-year-old high school senior doesn't apologize for circulating a critical letter about the citywide Student Advisory Council.

The administrator, Charlotte Hutton, is chief of the school system's student affairs office, which is supposed to advise the council and help set up its programs.

The student, Natasha Pearl, is a member of the student government group, representing Wilson Senior High School, Nebraska Avenue and Chesapeake streets NW.

In early March, Pearl addressed a four-page letter to Associate Superintendent Harris Taylor, Hutton's superior, complaining that elections being held for council officers were "a sham, as has been the SAC this entire year, functioning/mal-functioning under Mrs. Hutton's direction."

Pearl distributed 134 copies of her letter to such people as D.C. School Board members, student council presidents and junior and senior high school principals throughout the city.

Taylor, who supervises Hutton's office, sent a mild reply, defending the elections but inviting Pearl to make suggestions on how to get more students to participate.

Last week Hutton sent her own reply - with copies to the same 134 people who received Pearl's letter.

"Your extremely critical letter, so full of negatism, uninvestigated statements, and pugnacious verbalization," she wrote, "left me feeling quite concerned about your sudden behavorial indifference. I also have some question about your rationale, your motivation or whatever - all of which were completely inconsistent with your usual ex-emplary manner, dignity, integrity, and more importantly, our relationship . . .

"Since you took the liberty to address my supervisor in an effort to commit defamation of my character and professional competence," Hutton concluded, "I am requesting that a written apology be sent to me and a copy . . . be forwarded to all persons to whom you sent copies of your letter. If you have not responded to this request by April 24, 1978, I propose to seek legal counsel."

Pearl, who works as a volunteer aide to Del. Walter Fauntroy (D-D.C.) and plans to attend Harvard University next year, said she did not send a letter of apology to Hutton and does not intend to do so.

"I feel there's nothing I have to apologize for," she said. "Free speech is my prerogative. I wrote a letter that's critical, but I think I was critical in a positive way."

Hutton said she had not received any direct word from Pearl and would not comment on the dispute. "I have nothing to state on any of (it)," she said. "I'm going to see what will happen."

Meanwhile, two School Board members, Frank Shaffer-Corona and Barbara Lett Simmons, have strongly reprimanded Hutton and asked that she apologize to Pearl rather vice-versa.

"Mrs. Hutton's best action now would be her resignation," said Shaffer-Corona. "She's the one that owes an apology."

Simmons, who is a partner with Pearl's mother in an educational consulting firm, described Hutton's letter as "psychological intimidation." It was written, she said, in "non-English."

"This letter might shed some light on why we have concerns about our children's handling of standard English," Simmons remarked.

Hutton declined to comment on either Simmons' or Shaffer-Corona's remarks.

Along with stirring controversy, however, Pearl has made some headway.

Besides sending her letter, she attended a School Board committee meeting in late March. There she repeated her charge that the advisory council election was undemocratic because the nominees on the ballot came from only three of the city's 18 senior high and vocational schools and only five of the 30 junior highs.

In addition, Pearl said, the organization has no constitution to tell what the council and its officers are supposed to do. For the past few years, she said, the group has done little.

Last week the full D.C. School Board decided that the advisory council's new officers would not be installed until the group has a "democratic constitution."

Pearl said she and students from four other schools now are drafting one.

"We want a democratic association," she said, "that will serve as the official voice of students in D.C. to the School Board and the administration, not just a group that listens to lectures (by school officials)."

School Superintendent Vincent E. Reed said he agrees that student governments should have a strong citywide group, but he declined to comment on the exchange of letters between Hutton and Pearl.

"Mr. (Harris) Taylor is investigating it now," Reed said, "and he'll report to me . . . I've been too busy to worry about that . We get hundreds of letters all the time."