The utility model discloses a small -size instrument that lifts by crane, it is including setting up the wheel of controlling on the walking track, be fixed with the support frame respectively on controlling the wheel, be fixed with the backup pad between two support frames, install the gear stand in the backup pad, the connection is rotated and the other end of the gear shaft of swing pinion rotates the connection in the backup pad on the gear stand to an one end of following the gear shaft of the swing pinion of horizontal direction setting, the swing pinion goes out epaxial drive gear meshing setting with the transferred that revolves who installs on the engine, be fixed with the swinging boom on the gear stand, install the counter weight on the swinging boom, hoist engine and support column, the fixed pulley is installed respectively to front end and rear end at the support column, wire rope's one end links to each other with the hoist engine and the other end links to each other with the hoist and mount piece is fixed behind two fixed pulleys. This structure simple and easy, easy ann tear open, easy operation, and it is convenient to be under construction, improves the efficiency of construction, about reduce cost 50%.