Abstract: It is known that the life of high-power three-phase AC asynchronous motor will be greatly shortened by strong starting current. A method to overcome this shortcoming is the use of JQB₂ series starting controller with excellent performance. In this paper, the designing approaches of JQB₂ series auto-decompression starting controller are described. The matching between parameters of the electrical components is carefully selected and a set of compensating circuit is added. Compared with the general auto-decompression starter, the new starting controller reduces greatly the initial current and strengthens the starting torque. Furthermore, it also reduces the voltage drop of the electricity grid and capacity demand of power transformer, which is beneficial to improving the quality of the power grid. The simulation test shows that the JQB₂ starting controller achieves the designed starting effect. It seems that the described approaches have a good prospect of application.