Abstract: A nonlinear equation fitting method by the Programming Tool of the Microsoft Office Excel software was introduced in detail and its application in real data analysis was discussed. The experiment data of paramecium from Gause was used to investigate the efficiency of the method. And the twelve nonlinear real examples from “Agricultural Experimental Statistics” written by Mo Huidong were used to compare the difference between results fit by the Excel and the linear transformation method, respectively. The result showed that the Excel fitting method is not only simple and efficient for the parameter estimation but can fit various complex nonlinear equations also.