The invention discloses a cascading alarm apparatus and method for communication device. The alarm apparatus comprises a communication device rack and a plurality of communication devices arranged inside the communication device rack. Each communication device is provided with two identical alarm interfaces and a rack top reported alarm outputting interface on the communication device rack. The reported alarm interfaces of the communication devices are in serial connection according to their arranging sequence through reported alarm connection lines. The rack top reported alarm outputting interfaces are used to output the reported alarm signal to a sound-and-light used alarm reporting device. According to the invention, the reported alarm interfaces of the communication devices are in cascade connections, and only with one rack top reported alarm outputting interface, the communication devices are connected with a sound-and-light used alarm reporting device; when one or more than one of the communication devices in cascade connections report(s) an alarm, the sound-and-light used alarm reporting device generates an alarm accordingly. This effectively reduces the number required for the rack top reported alarm outputting interfaces and greatly reduces the wiring resources for the output of reported alarms in a machine room as well as the occupation rate of the sound-and-light used alarm reporting device, therefore, making the wiring for outputting reported alarm simpler and making the real time monitoring on reported alarm among the communication devices in a machine room more convenient.