In the CDMA cellular networking system, power control is a very important issue because it is an interference limited system. In order to reduce the near-far problem and improve the battery life of mobile station, the transmit power of mobile stations must be controlled to limit interference. In this paper, we study the effect of power control on system performance. Different power control rates may have influence on the performance. Meanwhile, we take the consideration of different call admission control algorithm. By introducing soft handoff waiting queue and guard channel into the soft handoff algorithm, we compare the power control influence on a base case (which is similar to IS95 algorithm, but with perfect power control) and proposed call admission control algorithm. The simulation shows that increasing power control rate and combination of power control and soft handoff prioritization can greatly reduce the blocking rates and refuse rates of new/soft handoff calls, thus the system performance is improved.