Aiming at the problems of slow data transmission, low fusion accuracy and long adaptation time of gateway heterogeneous protocol adaptation methods in the current transmission Internet of things, a research method of transmission Internet of things gateway heterogeneous protocol adaptation based on common edge nodes is proposed. Using the covariance matrix of the gateway node in the local state, the redundant data of the gateway heterogeneous protocol is eliminated. By describing the total variance of the characteristic deviation of the fused heterogeneous protocol, the farthest and nearest distances between the characteristic values of any two heterogeneous protocols are calculated. The heterogeneous protocols are fused by calculating the error between the characteristic value of the gateway heterogeneous protocol and the real value, Based on the design of heterogeneous protocol adaptation process, the adaptation of gateway heterogeneous protocol is realized. The experimental results show that the gateway heterogeneous protocol adaptation method based on common edge nodes can control the error rate between - 5% ~ 5%, the time is generally less than 3min, and the network throughput is about 920bps. Its practical performance is higher than the existing methods, which improves the adaptation ability of gateway heterogeneous protocols in the transmission Internet of things.