As a latest signal analysis toolkit,wavelet transform receives increasing interest from scholars.However, the correlation between the wavelet scale and frequency is an outstanding problem.This paper proposed a sinusoid model to estimate the central frequency of mother wavelets,besides,the model is generalized to the situation of arbitrary sample interval and arbitrary scale of wavelet.Moreover,traditional gradient-based optimization method will find local optimum due to the non-convex property of the model,therefore,a novel Rossler-attractor based Particle Swarm Optimization(RPSO)method was proposed.Experiments gave the center frequencies of all common wave-lets,and applied the proposed method in the field communication signal detection to validate its effectiveness and efficiency.