The invention provides a parameter testing method and system for a high-power centralized reactive power compensation device, and the method comprises the steps: carrying out the hardware-in-loop connection of a pre-built real-time simulation model and a high-power centralized reactive power compensation device controller, and building a parameter testing platform; acquiring the grid-connected current and the grid-connected point voltage of a high-power centralized reactive power compensation device controller under various test working conditions based on the parameter test platform; and integrating the grid-connected current and the grid-connected point voltage under each working condition, and determining a parameter value of the reactive power compensation device. The controller of thehigh-power centralized reactive power compensation device is tested, and the control algorithm is consistent with the algorithm of the device in actual work, so that the real control performance of the high-power centralized reactive power compensation device can be comprehensively reflected; and requirements of parameter testing are met.