The invention requests to protect a communication mode access selection method for a smart distribution grid heterogeneous wireless network. When the network state or network demand of the current communication mode at a time moment t changes, the index values of GPRS, LTE, 3G, micro-power wireless and WIFI communication modes at a time moment t-1 and at the time moment t are acquired, including received signal strength, network bandwidth, network delay and packet loss rate; an initial decision matrix is constructed, and the initial decision matrix is processed in a dimensionless manner to obtain a dimensionless matrix; a first weight vector a1 of the index is obtained by an entropy weight method; a second weight vector a2 of the index is obtained based on a rough set theory; a1 and a2 are integrated to obtain a final index weight vector a; a correlation coefficient matrix is constructed by a grey correlation method based on the dimensionless matrix; and the communication mode with the optimal performance at the time moment t is decided based on the correlation coefficient matrix and the final index weight vector a. By adopting the method of the invention, the traffic blocking rate of the smart distribution grid can be effectively reduced, load balancing of a smart distribution grid communication network can be facilitated, and the reliability of service transmission of the smart distribution grid can be improved.