This invention discloses a method for realizing audio fault self-diagnosis of an H.248 protocol of a home gateway. The method specifically comprises the following steps: establishing an independent H.248 fault self-diagnosis program in the home gateway, and interacting with an H.248 audio program in a manner of inter-process communication; classifying and filtering each key event by the H.248 fault self-diagnosis program, establishing corresponding state machines according to the types of the events to perform diagnosis and analysis for each type of events, and recording diagnosis results on diagnosis linked lists of corresponding types; on a user interface, acquiring and outputting fault recording information to the user interface to display by the H.248 fault self-diagnosis program according to the user requests. The method provided in the invention does not increase the hardware cost, has little influence to the existing audio function, and outputs the fault diagnosis results in simple languages so that engineers can quickly acquire the fault reason and handle the fault in time.