In order to meet the needs of data transmission among multiple devices in satellite onboard equipment, the multi-bus protocol controller based on SpaceWire provides 4 SpaceWire ports, 1 host control interface, 6 general-purpose UART interfaces, 16 SPI master interfaces, 4 SPI slave interfaces and 2 I2C interfaces to implement data interaction between SpaceWire interface and host control interface, SPI interface, UART interface and I2C interface. The multi-bus protocol controller is compatible with the latest SpaceWire standard ECSS-E-ST-50-12C Rev.1 and also supports the ECSS-E-ST-50-51C, 52C and 53C protocols. This controller can monitor SpaceWire link data flow and is capable of error detection and retransmission of SpaceWire packets to ensure the reliability of data transmission. The multi-bus protocol controller supports the transmitting and receiving of broadcast codes and also provides the function of slot planning based on timecode to enable data deterministic transmission. The multi-bus protocol controller can operate at data-rates between 2Mbps and 400Mbps per SpaceWire port and it has 64 time slots with 8 breakpoints in each time slot for fine deterministic and effective data processing capabilities. The host control interface has a large FIFO capacity of 16K bytes for both transmitter and receiver and the interface bus width can be configured as 8/16/32 bits. The UART interface can be connected to RS232, RS422, RS485, LVDS, M-LVDS transceiver circuits to form a powerful multi-bus protocol network.