The related components of material testing machine (e.g., pressure plate, pressure head, compression bar, etc.) produce distortion in the experiment. It is obviously irrational to use the stroke to replace the specimen displacement, which can’t be measured directly by the extensometer in the destructive test. Therefore, the evolution of specimen displacement, machine displacement and stroke of 45 steel, duralumin alloy and sandstone was analyzed under uniaxial monotonic loading and uniaxial cyclic loading. The results show that the deformation of the related components of universal testing machine, which increases/decreases along with the increase/ decrease of load, can’t be ignored. And there is a good one-to-one correspondence between the machine displacement and the load. It also has nothing to do with the types of specimen materials and the experiments. The relationship of machine displacement and the load can be used to determine the specimen displacement indirectly.