This paper presents a novel approach and provides equations for analysis and design of third-order charge pump PLL to desired specifications such as phase margin, damping ratio and given small signal settling time. This method is based on dominate pole approximation. Actually, the results obtained for second-order PLL can be used as approximation in the design of third-order PLLs. The performance of this method has been verified in two examples. Simulation results of the introduced method demonstrate precision in designed parameters. This method advantages are simple learning and very good precision.