The invention discloses an environment acquiring control comprehensive system access device. The device comprises a casing, a conversion circuit which is arranged in the casing, and a number of switching value input physical interfaces, switching value output physical interfaces, RS485 physical interfaces, RS232 physical interfaces, RS422 physical interfaces, Ethernet interfaces and the like, wherein a number of switching value input physical interfaces, switching value output physical interfaces, RS485 physical interfaces, RS232 physical interfaces, RS422 physical interfaces, Ethernet interfaces and the like are arranged on the side of the casing. The conversion circuit comprises a central processor unit, a switching value input/output interface module which is connected with the central processor unit, an RS485 communication interface module, an RS232 communication interface module, an RS422 communication interface module, a reset circuit module and a power supply module. On the basis that the original serial device is not replaced, the networking of a lot of serial port devices can be realized. The serial communication problems that the communication distance of the serial port devices is short, unified management cannot be carried out on the acquiring, the control and the like of a lot of switching values and the like are successfully solved.