Florida developer Stuart S. Golding signed a 92-page agreement with the government yesterday to begin restoration of the Willard Hotel near the White House within one year or surrender his development rights.

Golding pointed to signs that construction interest rates -- as high as 23 percent a month ago -- have begun to subside and therefore should enable him to keep his commitment. However, he added, if rates do not come down to "somewhere in the 12 percent area" by April 1981, "then it would be impossible" to go forward with the $70 million historic restoration on the now-vacant structure.

Earlier this month, Golding had asked the Pennsylvania Avenue Development Corporation, which was set up by Congress to restore the ceremonial route between the White House and the Capital, to give him an additional six months' leeway in the contract. That would have delayed construction possibly until October 1981. The corporation refused.

The hotel is being redeveloped in conjuction with the San Francisco-base Fairmont Hotel Corp.

Under the 99-year lease agreement signed yesterday, the government corporation agreed to demolish the small buildings between the Willard and the Hotel Washington and turn over the cleared land to Golding in four to six months.

At that point, Golding begins paying installments on an $800,000 annual rental fee to the government. Within six months of the turning over of the land, Golding must begin restoration work.

If not, the government can take back the project, and award it to another developer.