The invention relates to a communication indicating method and system. The indicating system comprises a main control module, a communication module, a gate module and a watchdog module. A hardware indicating signal sent by the communication module and a software indicating signal sent by the main control module are connected to two input ends of the gate module respectively, and the main control module is suitable for controlling the gate module to switch input channels through the waterdog module to output corresponding different indicating signals. The communication states of layers above a data link can also be indicated by multiplexing working states expressing a hardware layer and a software layer, namely, the communication state of a date link layer, through an indicating signal driving circuit; thus, when the demands for communication above the data link are met, frequent work of the indicating signals is not needed any more, and the service life can be prolonged; in addition, signals are gated through waterdog signal conversion to control switching of the input channels so as to output corresponding different indicating signals, and higher reliability is achieved compared with that of an indicating light designed in a traditional single software mode.