To estimate symbol rate of phaseshift keying（PSK）signals in high precision rapidly, a new algorithm is proposed after an analysis of the delaymultiply circuit. The new algorithm estimates symbol rate roughly by estimating the bandwidth of signal. Using with the rough estimation, the algorithm can estimate the symbol rate in high precision by the delaymultiply circuit. The validity is verified by computer simulations. This method is not only applicable to the symbol rate estimation of baseband signals, but also to the symbol rate estimation of modulated signals. The estimation accuracy of the proposed algorithm can be improved by increasing the number of sampling data when the sampling rate is fixed.