The invention discloses an OpenAPI conversion system and method based on a multi-Modbus bus protocol, and the system comprises the steps: employing an independent processing mechanism of each module,and building a connection state with manufacturer equipment through a serial port communication module, a TCP communication module, and a data access module under a plurality of Modbus protocols; achieving conversion between manufacturer data and upper-layer application system data through the data conversion module, so that data conversion does not need to be carried out again when a third-partysystem is in butt joint; adapting different-end storage modes of a manufacturer through self-defined data type codes; using a Modbus protocol analysis module to monitor the connection state with equipment of a manufacturer in real time, and automatically reestabihsing a connection when a connection fault occurs. According to the invention, through configuration, the Modbus standard protocol is adapted to perform unified deployment, a plurality of Modbus TCP/IP bus devices and a plurality of Modbus serial bus devices can be supported at the same time, and secondary development is reduced to themaximum extent or even avoided; data acquisition is reported in a unified manner, and data consistency is kept; and by effectively filtering the reported data, the data processing pressure of the upper application system is reduced.