Abstract: Population is the basic unit of community structure and function, and dominant populations in community play a key role in the formation of community structure and environment. However, it is still unknown how the dominant population works on the formation of community structure and what is the relationship between them. To answer this, a field investigation was conducted in mountain Leigong dealing with the total number of 41 of 4 m .4 m quadrats in 656 m2 of shrubbery. SPSS 17.0 was used to analyze the relationship between the parameter of population and community structure. The results showed that, the partial correlation coefficients of species richness index D and the crude density, diffusion coefficient of population and average plant height of the dominant population in plant community are respectively -0.927***, -0.928***and -0.913***, presenting negative correlation, namely that, the species diversity diminishes with the increased number of dominant populations crude density, diffusion coefficient and average plant height of the dominant population. More individuals of the dominant population in plant community are not conducive to plant community diversity. The work further validates the dominant populations position and role in plant community.