Real estate agent Clark L. Massie resigned yesterday from the Fairfax County Board of Zoning Appeals after disclosure that he is still under investigation by the Virginia Real Estate Commission for claims he allegedly made in 1977 about property in the Reston area.

Massie, who has been accused of telling prospective customers in the Stratton Woods subdivision their homes would be bordered by parkland that is actually the route of a proposed highway, submitted his resignation to Fairfax Chief Circuit Court Judge Barnard F. Jennings. In his letter of resignation Massie cited a Washington Post article that disclosed the state agency is continuing to investigate the allegations against him.

"I acquiesced to the submission of my name for the appointment with full knowledge of the matters set forth in the article," Massie said in the letter. "I believe it is in the best interest of all involved that I submit, effective immediately, my resignation from the board until all questions raised in the article have been resolved."

The seven-member zoning board has final control over the granting of exceptions to county zoning regulations, a power that makes it one of the most influential governmental bodies in the fast-growing county.

"He Massie submitted the resignation voluntarily," said Jennings, who had named Massie to the board Oct. 26. "I did not ask for it."

The judge said in an interview he was unaware of the state investigation at the time of the appointment. Massie could not be reached for comment.

Fairfax Board of Supervisors Chairman John F. Herrity, who had recommended Massie for the appointment, announced the resignation and said it "is in the best interest of the citizens of Fairfax County."

The Real Estate Commission opened its investigation of Massie two years ago and offered to terminate the inquiry if Massie would agree to a six-month suspension of his real estate license, according to Ronald B. Mallard, director of the Fairfax Department of Consumer Affairs.

Massie rejected the proposed settlement and asked that the matter be delayed until lawsuits over the issue were resolved. Three lawsuits filed against Massie and the companies he represented in the home sales were settled out of court in 1981, but state officials said the real estate commission's investigation remains open.

"I assumed that the termination of the civil suits brought against me through the out-of-court settlements ended any question concerning the matters involved in the suits," Massie said in his letter. "To my knowledge at the time of the appointment, no further actions were contemplated by the Real Estate Commission."