The on-site test and the commissioning of35kV±200Mvar cascade static synchronous compensator（STATCOM） in China Southern power grid are introduced.The technical matters such as:start-up and stop test，operation test，dynamic characteristic test，two-set coordinated controlling test，operating range and hot operation test，and redundance test are discussed.The on-site test results show that:STATCOM start-up and stop，the emergency stop，the control with constant var output and constant voltage，and coordinated controlling of two sets，etc.meet the design requirements，and the operation is stable;STATCOM can complete the output regulation within35ms under±20Mvar step change;when capacitor or reactor is switched on or off，STATCOM can complete the output regulation within20ms with a smooth transition without shock.The valve unit fault simulating test shows that the lock，the bypass，the restart and the tripping protection meet the design requirements.The test results also show that the DC voltage balance problem of STATCOM with considering the double objective optimization control strategy of500kV and 220 kV bus voltage，the output current harmonics and the energy-saving operation are still need to be studied further.