This paper puts forword a link quality evaluation technology based on the direction of antenna array. Link quality evaluation technology includes the initial link quality evaluation and continuous link quality evaluation. In the stage of a new node joining the net, initial link quality evaluation detects the RSSI value of the physical based on wireless Mesh network antenna array, and calculates the average RSSI, builds RSSI matrix. Then adopts a good quality channel according to the RSSI matrix values to build the link. Continuous link quality evaluation can monitor the change trend of RSSI continually, evaluates and adjusts the link modulation rate according to the packet error rate of the selected channel. The experiment results indicates that the initial link quality evaluation and continuous link quality evaluation can apperceive the change of all link quality, and adjust to the suitable modulation rate. Link quality evaluation technology can raise the utilization ratio of the bandwidth of the wireless network within a certain scope.