Based on the fact that linear active disturbance rejection controller (LADRC) cannot cope with q-axis current mutation and parameter setting defects in the compound control of speed and current of permanent magnet synchronous motor (PMSM), an improved ADRC is proposed. Firstly, the design method of conventional LADRC in the compound control of speed and current is analyzed. Secondly, based on the conventional LADRC, the fastest control synthesis function (fhan) is used to replace the proportion of differential (PD) to design the control law, improve the system control performance and optimize the parameter configuration mode. At the same time, based on the function characteristics, the current outer loop controller is designed, and the current deviation feedback algorithm is used to limit the q-axis current, so as to avoid excessive current impact damaging the hardware. Through the establishment of the experimental platform, the experimental results show that the improved LADRC can effectively deal with the q-axis current impact, which has the same anti-interference ability as the traditional LADRC, and reduces the transient response time of disturbance by 20 ms. It shows that the improved LADRC has higher safety performance and good anti-interference ability.