Spatial signatures often reveal ecological processes, and spatial pattern analysis is an important method for studying population characteristics, interspecies relationships, and the relationships between population and the environment. Due to the distinctive characteristics and the current situation of Quercus mongolica in China, it is necessary to investigate the ecological processes in Q. mongolica stands. To realize the status and development tendency of the Q. mongolica population in the Q. mongolica natural secondary forest, its spatial patterns were studied based on two permanent sample plots(plot A and plot B) with different compositions and structures(i.e.,different coenotypes) over an area of 1hm²(100m×100m) in Tazigou Forest Farm of Wangqing Forestry Bureau, Jilin province. The essential features, which include species identity, diameter at breast height(DBH), tree height, clear bole height, crown breadth, and coordinate information of each tree(DBH ≥ 1), of the two plots were surveyed by the adjacent grid method(10m×10m). Using the method of diameter class(instead of the age), Q. mongolica was divided into four different growth stages:stage I(1cm ≤ DBH < 10cm), stage Ⅱ(10cm ≤ DBH < 20cm), stage Ⅲ(20cm ≤ DBH < 30cm), stage IV(DBH ≥ 30cm). In accordance with the spatial point pattern theory, univariate pair-correlation function g₁(r), bivariate pair-correlation function g₁₂(r), mark correlation function k_mm(r), and mark variogram function γ(r) were adopted to evaluate the spatial patterns of Q. mongolica in different communities at various scales. The results showed that(1) All Q. mongolica populations in the two plots showed random spatial distribution at large scales, and the aggregated distribution was mainly concentrated at medium and small scales. The aggregated distribution at stages I and Ⅱ at medium and small scales was the primary cause for the above phenomenon. Uniform distribution was not observed in the two plots at all scales. The aggregated distribution of Q. mongolica in plot A is stronger than that in plot B.(2) The spatial associations of Q. mongolica among the stages I, Ⅱ, and Ⅲ in plot A are positive at medium and small scales. The spatial associations between older age and younger age classes were negative, especially between the stages IV, I, and Ⅱ. In plot B, however, negative spatial association was scarcely observed at all scales. The relationships between different stages were mostly uncorrelated with positive spatial association at small scale and low intensity.(3) The spatial autocorrelation of plot A is stronger than that of plot B, and the conspicuous expression mainly appears at DBH. The spatial autocorrelation of plot B for DBH and height is weakened to some extent compared to that of plot A. These results demonstrated that the spatial patterns of Q. mongolica are affected by the space scale of the sample plot, the growth stage of species, and the developmental stage of the community. This helps us to understand the current situation, growth characteristics, and developmental tendency of Q. mongolica population and its natural secondary forest, and can provide an important reference for sustainable forest management and ecosystem conservation in the Q. mongolica natural secondary forest area of northeast China.