Abstract: Following the paper application of Kalman filtering method in growth models (Ⅰ), this paper deals with the growth estimation of chinese fir by use of Kalman filtering method associated with growth model (Ⅱ) built by the second order difference method. The results show that difference growth model and Kalman filtering mothod can be used to describe the growth of trees better. This paper also provides a new method to estimate tree growth.