An adjustable underwater pipe clamp device comprises a main support pipe, a main support pipe clamp, two branch support pipes, two branch support pipe clamps, a cable protecting pipe clamp and a vertical pipe clamp, and is characterized in that the two branch support pipes and the two branch support pipe clamps are mounted on the main support pipe, the branch support pipes are connected with the vertical pipe clamp and a vertical pipe, the two branch support pipes are connected with the cable protecting pipe clamp and a cable protecting pipe, and the main support pipe is connected with a guide pipe frame structure rod and the main support pipe clamp. By 'one clamp for two pipes' mounting way, only one main pipe clamp is connected with the guide pipe frame structure rod, unoccupied positions on various horizontal structure rods of a guide pipe frame can be reasonably used. The main pipe clamp and the branch pipe clamps are adjustable, requirement for size accuracy is met, and offshore mounting success rate is increased. Integral offshore mounting of the vertical pipe and the cable protecting pipe can be realized, offshore construction period is effectively shortened, and mounting cost is greatly reduced.