Abstract: Basing on the natural broad-leaved forest which was not intervened by human beings in the north of Fujian,the growth model for the stand was established and the forecast method was put forwarded.After obtaining each stand factor of the subcompartment in forestry management investigation,the subcompartment forestry resource dates of the former stand can be forecasted continually and renewed dynamically by using the model and the method,the stand relative density index was posed and a natural thin model was put forwarded academically basing on the power function relationship between the stand individual of the maximum density and average breast-height diameter,a practical and possible way was afforded to master the dynamical density of the stand and use the growth model to forecast that stand dynamically.