About 30 Mission Hill resident picketed Saturday's Medical School commencement activities to protest a proposed Medical School area power plant.

The demonstrators chanted "Harvard out of Mission Hill" and "Build a power plant in your own yard, not mine," and marched peacefully in front of Longwood Quadrangle, where the graduation ceremonies took place.

Some of the demonstrators, who claim to live in homes slated for demolition to make room for the proposed $48-million power plant, said they object to recently received eviction notices sent out by Harvard, the Landlord of the properties.

Donald C. Moulton, assistant vice president for community affairs said yesterday the residents still living in the area have known for a long time that houses in the area are slated for demolition.

"As of my last count taken last week, most of the people living in that area knew where they were going to move to," Moulton said.

Abandoned Dwellings

Most of the 97 dwelling units bounded by Brookline Ave., and Peabody. Binney and Frances Sts., where the proposed power plant is to be built, have already been abandoned.

Moulton said the University has plans to build 775 units of low and moderate-income housing by 1977 near the Mission Hill area, which will accommodate any residents dislocated by the power plant.

He said the power plant site is "part of an institutional area slated for in- situational development, anyway."

Herbert Shaw, director of the Medical Information in the University News Office, said yesterday that although the professors had a bullhorn, they did not disturb the commencement proceedings.

Robert Parks, president of the Roxbury Tenants of Harvard (RTH), a group the University recognizes as the official bargaining agent for the residents of the area, said last night that the protesters were not connected with RTH and he does not know "anything about it."

An environmental impact statement released two-and-a-half weeks ago by the Boston Redevelopment Authority, said the power plant would have a minimal impact on surrounding areas.

The power plant is designed to provide electricity, steam, chilled water and refuse incineration for the Medical School and nearby medical facilities in the Brookline-Huntington area.

A public hearing on the impact statement will be held this Wednesday evening at the Medical School's Countway Library