Abstract: Based on the investigations in Chinese fir orchard,crow index can be used, as a comprehensive index, to describe the state of tree growth this paper analyzed the relationship between stand growing, especially crown dynamics,and seed yields.The results indicated that while crown index was between 2.5 and 4.5,the seed tree could produce more seeds,and the optimum crown index was 3.5. On the basis of result in this paper,the stand density in the Chinese fir orchard could be controlled easily,effectively and correctly according to variations in crown heights and crown diameters.