In the current method, the evaluation of multi-mode protocol adaptation is poor. When dealing with multi-mode protocol adaptation and heterogeneous network fusion, the problems of low reliability, high blocking rate, and high packet loss rate are addressed. A new multi-mode protocol adaptation and heterogeneous network fusion method is proposed. The method consists of two steps: multi-mode protocol adaptation and heterogeneous network fusion. First, the multi-mode protocol adaptation model is used to implement the heterogeneous network multi-mode protocol differential format conversion, and the heterogeneous network data in the multi-mode protocol is uniformly converted to the same Format; and then for the converted data, through a new heterogeneous data fusion algorithm, to achieve heterogeneous network communication data fusion. Finally, the UMTS + WLAN multi-mode protocol adaptation and heterogeneous network fusion problems are used as examples to implement the fusion effect test. The test results show that the method has minimal delay, availability, and reliability when dealing with heterogeneous network fusion problems. The test results of blocking rate and packet loss rate are better than the comparison method.