In this paper,a four-parameter least square sine wave curve-fit method based on the frequency estimation method and realized by using the three-parameter sine wave curve-fit method is introduced.The features of it are: 1)absolute convergence;2)without the pre-estimation of parameters;3)simple and easy to be realized;4)no iteration;5)high speed calculation course.The simulation results have proved the correctness,rightness and the defect of this method.