The article designs a high-voltage PTC control system for new energy vehicles. Its control circuit is on the high-voltage side and isolates the CAN circuit from the communication circuit of the control system. This control system has a power-off holding function，which can be used for PTC fault handling. The control system realizes overvoltage,undervoltage，and overcurrent protection functions through both hardware and software. The control system divides the power circuit into two，which improves the reliability of the power device while reducing the transient inrush current. Verified by the simulated vehicle test.