In order to improve the power angle stability and voltage stability of power system that contains static var compensator (SVC), this paper puts forward a SVC nonlinear controller (SNC) based on synergetic control theory. The macro variables and manifold are designed considering the voltage stability and power angle stability, then the analytical expression of the control of static var compensator based on synergetic control is derived, and the determination principle of each control parameter is discussed. The designed SNC is applied to a two-area system and IEEE9 node system, which is verified by PSCAD/EMTDC simulation. Compared with the SVC conventional supplementary controller (CSC), the proposed SNC in this paper is more effective to stabilize the voltage of the system while providing damping to the system. This work is supported by Key Research Funds for the Central Universities (No. 2015ZZ017) and National Natural Science Foundation of China (No. 51107042).