Abstract: When the hydraulic support is subjected to an internal loading test, a certain pressure working medium is applied to the lower cavity of the hydraulic support legs to make the leg support force reach a specific coefficient of working resistance, and this force is used as the test force of the hydraulic support. However, due to the installation angle of the hydraulic support legs, and the friction between hydraulic support canopy and test bed, the test force is actually a component of the support force of the hydraulic support legs, there is a large error between the test force and the actual value. In order to solve this problem, this paper analyzes the internal loading test working condition of 2-leg shield hydraulic support, and the difference between the test force and the legs support force is obtained, then it designs a direct force measuring device, after testing the test force of hydraulic support with different working resistance, it is concluded that the actual test force should be 8% ~ 18% higher than the current loading force, and the technical problem that the test force of hydraulic support cannot be accurately measured is solved.