The invention relates to an optical network-based automobile electric system. The optical network-based automobile electric system comprises a main optical fiber, a sensor, an optical receiving and transmitting assembly, a gateway and a peripheral assembly of an automobile, wherein an electric signal measured by the sensor can be converted into an optical signal through the optical receiving and transmitting assembly and can be transmitted to the peripheral assembly of the automobile through a main network, the gateway and the optical receiving and transmitting assembly; the peripheral assembly of the automobile comprises an engine ECU (Electronic Control Unit), a transmission system TCU (Transmission Control Unit), a brake system ABS (Anti-lock Brake System), a light control ECU, a door and window control ECU, a power distribution ECU, an antitheft ECU, an SRS (Supplementary Restraint System) ECU, a back-up ECU, an entertainment terminal and a navigation unit. According to the optical network-based automobile electric system disclosed by the invention, an optical control signal can be transmitted through the main optical fiber, not only can the problems of electric short circuit, electromagnetic disturbance and degraded and melt-down circuit be completely avoided by a control circuit, but also various communication protocols including CAN (Controller Area Network), LIN (Local Interconnect Network), FlexRay and MOST (Media Oriented System Transport) can be simultaneously compatible, a video signal can be quickly transmitted, and the requirements on high speed and sharing of information of the automobile can be met.