The invention discloses a transparent transmission system and a transparent transmission method for a message of substation equipment. The function of locally debugging field equipment is achieved in a serial port to network mode. Due to the adoption of the serial port to network mode, transparent transmission has the advantage that the limitation of a serial port transmission distance is avoided. A debugging operator only needs to set relevant parameters and needs to access a local transparent transmission PC (Personal Computer), so that the function of connecting with a serial port of the field equipment can be achieved, and the debugging operation is completed.