The comprehensive performance test bench of hydraulic pump with the test accuracy of class A was used to test the volume flow rate of hydraulic axial piston pump at different pressure difference and shaft speeds according to the type test requirements.Based on the test data, the no-load displacements of the pump were calculated and compared by using the zero-pressure intercept method, one-step TOET method and two-step TOET method, respectively.The results show that:the no-load displacements calculated by using the zero-pressure intercept method are significantly affected by the shaft speeds,especially at the low shaft speeds, there are great differences between the no-load displacement and the nominal displacement;the no-load displacements calculated by adopting the TOET method are more closely to the nominal displacement by comparing with the zero-pressure intercept method.The test data obtained from the conditions that exceeding the rated pressure or speed may lead to large deviation.