The National Park Service will spend $500,000 this year and next to refurbish its popular Rock Creek Park nature center and replace all the exhibits - except for Max the owl, the fish and the bees.

The 18-year-old nature center, near the Park Service's public stables at Military and Glover roads, still has most of the exhibits it had when it opened in 1960 as an indoor guide to outdoor Washington.

The new ecological exhibits, to be completed this year under a $275,000 congressional appropriation, will emphasize the interdependence of all living things, particularly plants, animals and birds native to the Rock Creek, said Park Service spokeswoman Mary Krug.

During the fiscal year which begins in October, the Park Service plans to spend $200,000 on a major interior renovation of the building, including replacement of all seats in the planetarium and auditorium, said Krug. The Park Service last year built new rest-rooms and entrances to make the center more accessible to the handicapped and has been planning the renovations in a $21,000 study.

The nature center, which costs $193,000 when it was built, helped open a new era of environmental education for the Park Service. The service later established the Green Scene to help area residents with flower and (v. ORD ILLEGIBLE problems, opened the Oxon Hill Children's Farm, began living history and environmental programs at Pierce Mill, Turkey Run and on board the Lightship Chesapeake, now moored off Maine Avenue, and greatly expanded the public use of other parkland here.

Rock Creek Park, established in 1890, was one of this country's first national parks and is still the largest park inside any U.S. city.

About 50,000 visitors a year, more of them children, now use the nature center, said Krug. Many of ecological exhibits, to be made at the Park Service's national exhibit branch at Harper's Ferry, "will give kids things to climb, to handle, to do, such as making sugar the way a plant does . . . adding sunlight and then turning a switch and adding carbon dioxide," said Krug.

The center's popular working bee hive, fish tank and resident pet owl, Max, will not be changed, she said.