The invention provides an SSSC novel nonlinear robust control system comprising a measurement module, a signal analog transformation module, a comparison module, a state space transition module, a central control module, a state space inverse transformation module, a voltage source converter gate trigger and control module and an SSSC module. The signal output end of the measurement module is connected with the signal input end of the SSSC module through the signal analog transformation module, the comparison module, the state space transition module, the control module, the state space inverse transformation module and the voltage source converter gate trigger and control module in turn. The signal output end of the SSSC module is connected with a power transmission system. The nonlinear robust control method is a continuous control method with no requirement for using a boundary function so that the nonlinear physical structure characteristics of a controlled object SSSC can be fully maintained and utilized and real-time control of the SSSC can also be performed.