Sandwich-type structure based on Salisbury screen effect is a simple and effective strategy to acquire high-performance terahertz (THz) absorption. The number of sandwich layer is the key factor that affects the absorption bandwidth and intensity of THz wave. Traditional metal/insulant/metal (M/I/M) absorber is difficult to construct multilayer structure because of low light transmittance of the surface metal film. Graphene exhibits huge advantages including broadband light absorption, low sheet resistance and high optical transparency, which are useful for high-quality THz absorber. In this work, we proposed a series of multilayer metal/PI/graphene (M/PI/G) absorber based on graphene Salisbury shielding. Numerical simulation and experimental demonstration were provided to explain the mechanism of graphene as resistive film for strong electric field. And it is important to improve the overall absorption performance of the absorber. In addition, the number of resonance peaks is found to increase by increasing the thickness of the dielectric layer in this experiment. The absorption broadband of our device is around 160%, greater than those previously reported THz absorber. Finally, this experiment successfully prepared the absorber on a polyethylene terephthalate (PET) substrate. The absorber has high practical feasibility and can be easily integrated with the semiconductor technology to make high efficient THz-oriented devices.