The VSC-HVDC transmission system has been widely used in power system of China. The reliability of its core equipment，the converter valve，directly affects the safe and stable operation of the power grid. With the emergence of harmonic oscillations in VSC-HVDC projects around the world，in the type test，in addition to meeting the experimental items specified in the IEC standard，the harmonic tolerance capability of the converter valve also needs to be assessed. For this reason，a harmonic current injection control method is proposed based on the converter valve type test platform. An equivalent model of the current control circuit is established，which is compared with the conventional current control strategy based on a proportional-resonance （PR） regulator. By comparison，it proves that the proposed harmonic current control method based on the second-order low-pass filter can significantly improve the amplitude-frequency characteristics of the current control loop and eliminate the steady-state fluctuations of injected harmonics. Finally，the PSCAD software is used to simulate and verify the proposed current control method，and the control performance of the steady-state harmonic current based on the conventional PR regulator and the second-order low-pass filter is compared，which shows the effectiveness of the proposed current control method. Further，test verification is carried out on the converter valve type test platform. In the steady state，the harmonic current tracks the given value，which can meet the engineering verification needs of the converter valve harmonic current stress.