As the core modulation technology of cascaded H-bridge static synchronous compensator (STATCOM), carrier phase-shifted SPWM (CPS-SPWM) technique is important for STATCOM output voltage precision and the real-time performance. The three pulse generating methods for CPS-SPWM technique, i.e. natural sampling method, symmetry rule sampling method and asymmetry rule sampling method, are analyzed and compared. Then, CPS-SPWM pulse phase shifting technology based on the asymmetry rule sampling is proposed to solve the problem of DSP control complexity, lack of hardware resources CPLD when the number of cascade H-bridge is large. The simulation results show that compared with traditional CPS-SPWM technology, the proposed method can ensure output characteristics of STATCOM and effectively reduce the hardware resources, which can simplify the circuit design and be easier for the engineering applications.