To transform the nonlinear equation to provide a mathematically equivalent linear equation is a common method for fitting logisitic equation in the past. But it will not yield the minimum residuals for the untransformed equation. In this paper, Marquardt's algorithm is used for determining the values of parameters in logisitic equation that will give the best least-squares fit to a set of data.The comparison of present method with the methods, used by Gause,And-rewartha, May, and Wan, are given in the paper...