The invention discloses a synchronization time-division multiplexing bus communication method adopting a serial communication interface. Data receiving lines and data delivery lines of a host machine and slave machines are all connected with a bus respectively. The method is that each slave machine receives data through a serial communication interface (SCI) when the host machine sends downstream data message correspondingly needed by each slave machine once, the slave machine begin to send upstream data message after a certain time interval, a next slave machine begin to send upstream data message after same time interval when a last slave machine sends the upstream data message, and the bus communication method is achieved and the like. Only two physical connection lines are used to achieve high-reliability difference connection on the basis possessed by most majority of microprogrammed control units (MCU), simultaneously high-speed real-time requirements can be met, a bus communication problem of an internal module of the device is solved, real-time controllable communication is achieved, complexity of a hardware circuit is reduced, and generality and reliability are strengthened.