CAPE CANAVERAL, Fla. (AP) _ Two more nuclear arms opponents were arrested today after they scaled a fence at Patrick Air Force Base, bringing to 39 the number of protesters arrested since Friday, authorities said.

Nuclear arms opponents are planning a rally Saturday at Cape Canaveral to protest the test-launching of an unarmed Trident II missile from the National Aeronautics and Space Administration facility. The government has not announced when the launch will take place, but protesters said it is expected this week.

About 200 marchers left Kings Bay, Ga., last month for the 200-mile walk to the Cape. Kings Bay is a future base for Trident missile-carrying submarines.

Since Friday, 39 people have been arrested for entering federal property. Most of those arrested are still in jails in Orange and Seminole counties, where they have refused to give their names.

The two protesters arrested today at the Air Force base 30 miles south of the Cape had scaled a fence and dashed to a nearby taxiway. They were turned over to the FBI on federal trespass charges.

On Tuesday, plans for a counterdemonstration were announced, and authorities also noted that an anti-abortion motorcade was planned for Saturday.

The counterdemonstration will be peaceful and no attempt will be made to confront the anti-nuclear protesters, said David Kraak, a subsitute teacher from Satellite Beach who said he is the spokesman of the group.

''This will be a silent demonstration,'' he said. ''Our silence and our American flags will be louder than any noise they can make.''