To investigate the formation process and mechanism of coarse woody debris (CWD) in the mixed broadleaved-Korean pine forest, point pattern analysis was used to study the spatial distribution and spatial association of CWD of different categories within a large permanent plot of 10.4 hm². The results showed that: (1) Overall, CWD exhibited an aggregated distribution at scales of 0-7 m, which transitioned to a random distribution as the scale increased. (2) The CWD of decomposition level 5 and logs exhibited a random distribution at all scales, while other CWD shifted from an aggregated distribution to a random distribution, but with different pattern scales (between 2-10 m). (3) Medium diameter class CWD and small diameter class CWD, as well as high decomposition level CWD and low decomposition level CWD, changed from being positively association (0-6 m) to being independent. Further investigation revealed that there was positive association (0-5 m) between high decomposition level CWD and low decomposition level CWD within each diameter class. Additionally, a positive association (0-4 m) was observed between decomposition level 2 CWD of large diameter class and small diameter class. Only the snags and logs had positive correlation (0-4 m). The association between CWD of Larix gmelinii and Picea koraiensis transitioned from positive (2-4 m) to negative (12-17 m), and then to independent. Positive correlations were found between CWD of Larix gmelinii and small diameter class, as well as decay class 2 of Picea koraiensis at scale of 0-3 m, while negative correlations were observed between CWD of Larix gmelinii and mid-diameter class, decay class 1 and 2 of Picea koraiensis at scale of 13-16 m. The formation of CWD in the mixed broadleaved-Korean pine forest may be attributed to tree species characteristics, individual competition at small scales, natural aging, external disturbances, habitat heterogeneity, and other factors. Large and medium diameter classes have a positive influence on small diameter class, earlier mortality has a positive effect on later mortality, the snags have a positive impact on logs. Larix gmelinii has a positive influence on Picea koraiensis individuals at a small scale but a negative influence at a slightly larger scale. This study provides insights into the formation process and mechanism of CWD in this forest type.