The invention discloses a device and method for ensuring reliability of a protection trip of an intelligent substation. The device comprises a main central processing unit (CPU), an auxiliary CPU, a main field programmable gate array (FPGA) and an auxiliary FPGA, wherein the main CPU and the auxiliary CPU are connected, the main FPGA and the auxiliary FPGA are connected, the main FPGA and the auxiliary FPGA are connected with a physical layer of a protection device, the main CPU and the auxiliary CPU are connected a state monitoring data output end of a protected device, the main CPU is used for sending a processing result to the main FPGA, the auxiliary CPU is used for sending the processing result to the auxiliary FPGA, and the auxiliary FPGA is used for synchronizing current information with the main FPGA after receiving information sent from the auxiliary CPU; and when the main FPGA receives tripping information, the main FPGA compares the consistency of the current tripping information acquired from the main CPU with the consistency of the current tripping information acquired from the auxiliary FPGA, if yes, the main FPGA sends the information received from the main CPU to the protection device, otherwise, the main FPGA abandons the information received from the main CPU. By the device, the misoperation prevention ability of the protection device is improved, and false operation of a primary device caused by an unknown error on the failure conditions of a hardware device, single event upset (SEU) and the like is ensured to be prevented.