In order to reduce the interference of the inter cell interference and improve the system capacity, the base station is studied in the form of heterogeneous network. In the case of multiple users, to maximize the sum of the edge user's rate, through setting the path loss threshold to select the base station for collaborative communication. The average rate of users in different clustering methods is analyzed and compared, and the reasonable threshold value is selected by observing the rate variation of different threshold values. The simulation results show that the clustering method has certain advantages in improving the transmission rate of the system compared with the previous power maximum method and threshold method.