Coarse woody debris (CWD) is one of the most important components in the structure and function of forest ecosystems and it is also key for maintaining system integrity and stability. Therefore, studying spatial patterns of CWD can help us understand the formation of population patterns and the maintenance mechanisms of forest ecosystems. Karst evergreen broadleaved mixed forest is one of the best preserved primordial subtropical forests. To date, there have been few studies of spatial patterns and correlations in this forest, especially research on CWD and its spatial distribution. The pair correlation function g(r) was used to study the spatial distribution patterns and correlations of CWD of different forms, decomposition levels, and diameter classes in a 1.28 hm² fixed plot in Maolan karst mixed evergreen and deciduous broadleaf forest. The results showed that 1) at a spatial scale of 40 m, overall CWD showed a clustered distribution at spatial scales ≤12 m. With an increase in scale, CWD tended to be randomly distributed. After removing habitat heterogeneity, the pattern scale was reduced to 7 m. 2) The distribution pattern of CWD diameter classes was: small tree > medium tree > large tree. CWD, in the form of root inversion and breakage at trunk, was randomly distributed throughout the study area and other types of CWD of different diameters, decay levels, and forms were clustered at a small scale (2-8 m). With an increase in scale, the intensity of aggregation decreased sharply and CWD tended to be randomly or regularly distributed. 3) Aside from the spatial independence of CWD between breakage at trunk and segment, and large and small diameter classes, there were significant positive correlations between different diameter classes, decay levels, and forms at a small scale of 2-8 m. With an increase in scale, the spatial correlation decreased. The distribution patterns of CWD in this Karst forest may be formed by ecological processes such as small-scale density restrictions, large-scale endogenous habitat filtration, and individual natural senescence. The large diameter, earlier mortality, and standing individuals had a positive effect on nearby small diameter, later mortality, and fallen individuals, respectively, which revealed the mechanism of natural regeneration of this forest type.