The invention discloses an experimental system and a method for simulating a composite load of an explosion shock wave and a single fragment. The method comprises steps of: determining parameters, such as the density and the length of a foamed aluminum projectile, the diameter and the depth of an opening, the length and the diameter of a fragment simulated projectile, and the launch speed of a composite projectile, according to the composite load parameters of the shock wave and the fragment desired simulated; preparing a composite projectile based on the determined composite projectile parameters; and ejecting the prepared composite projectile out of the primary light gas gun at the determined speed, thereby forming a composite load of the shock wave and the single fragment desired simulated. According to the experimental system and the method for simulating the composite load of the explosion shock wave and the single fragment a method for scientific researchers and engineering designers to simulate the explosive power of an explosive device with a shell is provided. The method can be widely applied to the simulation test of explosive impact loads in the fields of the transportation, the safety protection, the military, and the like; can effectively save the test cost; and has considerable economic benefits.