The utility model discloses an assembly pulley formula pneumatic cylinder loading test device, including the base, adjacent fixed be provided with mounting bracket and heavy object crane boom on the base, fixed mounting has the pneumatic cylinder of being tested in the mounting bracket, is connected with running block I in the tailpiece of the piston rod cephalad of pneumatic cylinder, and the cylinder body below of pneumatic cylinder is fixed and is provided with standing block I, surface mounting has standing block II under heavy object crane boom's the roof, and standing block II below is provided with running block II, and running block II has hung the heavy object downwards, being provided with wire rope's fixed point I on the base, being provided with fixed point II at heavy object crane boom's roof lower surface, wire rope from fixed point I draws forth walks around running block I, standing block I, standing block II, running block II in proper order, and wire rope's end ends in fixed point II. The utility model has the advantages of simple structure, the reliable operation.