The invention discloses a closed-loop control system and method for positive and reverse isolators. The system comprises a data communication module, a message segmenting module and an engineering maintenance module; the data communication module is used for organizing service data and positive heartbeat messages of a positive data channel and service data E files and reverse heartbeat files of a reverse data channel; the message segmenting module is used for ensuring that no packet splicing occurs in the TCP (transmission control protocol) long-link data transceiving mode; the engineering maintenance module allows a maintenance engineer to only need to locate the communication problem at one end of the positive and revere isolators. The problem that device crash or data transmission channel causes cannot be quickly located when service data transmission of the positive and reverse isolators is jammed is solved, and according to the application features of a high-safety communication model, the problem that maintenance crossing two ends of the positive and reverse isolators is difficult is solved.