D.C. Budget Director Betsy Reveal is resigning to take a higher-education post and Corporation Counsel Inez Smith Reid is taking a leave of absence, the Barry administration announced yesterday.

Officials stressed that the announcement of the two major personnel changes on the same day was a coincidence and that they would not result in a disruption in the city government.

"We have done such an outstanding job of running this city that the academic community is raiding my staff," Mayor Marion Barry said in a statement announcing the moves.

Reveal, who replaced Gladys Mack as budget director in January 1983, will leave city government Oct. 6 to take a permanent position as associate dean for administration at Harvard University's Kennedy School of Government.

Reid leaves her post as corporation counsel today to become a visiting professor at the University of West Virginia College of Law. She is expected to return to her job on May 16.

John Suda, principal deputy corporation counsel, will serve as acting corporation counsel while Reid is on leave, according to Tom Simms, special counsel for the corporation counsel.

Reid said she was taking a leave of absence "Because I had an offer I couldn't refuse, and the mayor was gracious enough to grant me a leave of absence to do something I love, which is to teach, research and write . . . . I gave the mayor my word I would be back on the 16th of May."

A former inspector general of the U.S. Environmental Protection Agency and associate professor at Barnard College in New York City, Reid has presided over the legal arm of the city government since September 1983 when she was promoted from deputy corporation counsel.

The office handles suits filed by and against the city, oversees prosecution of criminal cases, writes legislation for the mayor and performs various other legal functions.

The departure of Reveal, a highly regarded public administrator, came as a surprise and is expected to cause some disruption in the city's highly complicated budget process.

Alphonse G. Hill, deputy mayor for finance, will assume Reveal's duties until a permanent replacement can be found, according to Hill.

"I anticipate making sure the function is done until such time as we find an acceptable candidate," said Hill, who as deputy mayor oversees the budget office.

"We'll be looking high and wide, inside and outside to see what our options are. The government has to go on," he said.

The District is awaiting final action by Congress on its fiscal 1986 budget while agencies have begun preparing proposals for spending in fiscal 1987.

Reveal said the Harvard post was "not something I went to look for" and that she agonized over her decision to take the job.

Reveal, a master's-level graduate of the program at the Kennedy School, has served as chairman of the alumni executive council there.

Before becoming budget director, Reveal served from 1977 to 1980 as director of the city's office of criminal justice plans and analysis. She also has served as deputy director of the New York State Financial Control Board.