The Senate voted yesterday to appropriate $8.5 billion for military construction projects, including the first major spending for six new Navy ports in the Gulf of Mexico.

The measure, which passed 93 to 0, was sent to a House-Senate conference to be reconciled with the $8.3 billion version that the House passed July 17.

President Reagan asked for $10.1 billion for Pentagon construction for the fiscal year that began Oct. 1. But the House and Senate voted to reduce that request as part of the effort to cut federal spending and reduce the deficit.

Reagan sought $242 million for the Navy's "strategic home-porting plan," which calls for new ports to berth ships that the Navy will gain as part of the administration's program to increase the fleet from 450 to 600 ships.

The Navy says the ports are needed to protect the ships from a Pearl Harbor-type surprise attack, but critics charge that the real reason is to ensure Navy shipbuilding budgets are supported in future years.

The Senate measure passed yesterday includes the $242 million, while the House version proposes $172 million.

The Senate bill, like its House companion, includes language urging that U.S. allies in Europe assume a greater role in defending Europe and pay a bigger share of defense costs, though it doesn't contain specific goals.

The bill appropriates $368 million for a variety of NATO construction programs.