An electronic device, applied on a smart car with a plurality of sensors, includes at least one network switching circuit, at least one motherboard circuit, and a power supply circuit. The network switching circuit is coupled to the sensors of the smart car to receive sensing data from the sensors and to output the sensing data. The motherboard circuit includes a network interface controller and at least one CPU. The network interface controller is coupled to network switching circuit to receive the sensing data from the network switching circuit. The CPU is coupled to the network interface controller to perform autonomous driving for the smart car according to the sensing data. The number of network switching circuits and motherboard circuits depends on the autonomous driving level of the smart car.