Abstract: To understand the factors influencing the complex change of plantation，the field investigation of plant communities and environmental factors (elevation, slope, aspect, position, and the proportion of rock exposure) of actual Platycladus orienalis plantation in the low mountains and hills of Xuzhou were carried out, the communities were classified into four types based on the species composition and important values. And the total, disordered and structural complexity were measured using the mean length of Huffman code, the 12th order of Rényi entropy and the difference between these two measures, respectively. Then the correlation between the complexities and the species composition, the environmental factors were analyzed. The results revealed that the complexities of actual P. orienalis plantation differentiated, the complexities were influenced mainly by the species composition factors and environmental factors, the change tendency of the total and structure complexity in whole community and each layer was highly consistent, and was influenced mainly by the proportion of nondominant species composition, the disordered complexity was restricted mainly by the variation coefficient of species important value. Environmental factors influenced the complexities through effecting species composition. Therefore, the ways such as thinning, introduction, replanting and so on could be used to improve the forest structure, and to enhance the complexity and stability of actual P. orienalis plantation.