Abstract:Family of Pearson type was selected as the function of diameter distribution in this paper, and the moment of first order 4 about the orgin was used as a link with distribution function. By means of analytical technology of time series, it recommended a series of dynamic models to express and predict future diameter distribution of existing stand. The practical data from the man made Populus even-aged stand were used to examine the effects of these models and the result was satisfactory.