Abstract: In WCDMA, how to use the power control to decrease the transmittion power and lessen the system interference to upper the system capacity on the cond ition of assure the Qos users required is one of the keypoints. The main work of the paper is to analyze and summarize the power control in WCDMA, including the inner loop power control, outer loop power control, uplink power control, downl ink power control, coming up with one outer-loop power power control algorithm