This paper studied the negative pressure lifting method for spherical spent fuel elements in the high-temperature gas-cooled reactor HTR-PM. Appropriate measurement points for the spherical velocity in the spent fuel storage system were first selected. By adjusting the frequency of the fan, the spherical velocities at different measurement points were measured, which can determine the working range of the negative pressure lifting frequency of the fan. Due to the lack of the formal spherical velocity measurement equipment in the system, a temporary spherical detection device was installed during the commissioning process and then removed after the test. The current method can effectively guide the subsequent operation and control of the spent fuel storage system of high-temperature gas-cooled reactors. It can not only ensure the charging efficiency of the system but also avoid damage to the spent fuel elements caused by an excessive increase in the spherical velocity, thereby reducing the generation of radioactive gases and dust, and environmental pollution.