Monsoon evergreen broad-leaved forest (MEBF) is the climax vegetation type in the subtropics of China, and its structure and species composition have been shifting in the last 23 years. However, we know little about the dynamics of its interspecific associations. Our objective is to investigate the long-term dynamics of overall and pairwise interspecific associations in this forest community. In each community survey of the 1 hm² monitoring plot in the Dinghushan Biosphere Reserve, we recorded the species name, diameter at breast height (DBH), and tree height of every tree with DBH ≥ 1 cm. Up to now, seven surveys have occurred, in 1992, 1994, 1999, 2004, 2008, 2010, and 2015. In this study, we selected 29 dominant species according to their importance values, and studied the overall and pairwise interspecific associations by using variance ratio (VR) analysis and Spearman's rank correlation coefficient test, respectively, on the data from all surveys. From 1992 to 2015, the MEBF communities showed significant positive association; the VR values of all surveys were significantly > 1. However, in this period, the VR value of the community had decreased significantly (R²=0.93, P < 0.001), and the total significantly positively associated species pairs decreased significantly, while the total significantly negatively associated species pairs increased significantly. These results indicated that the positive associations in the MEBF community weakened over time, and the stability of the species composition of this forest had decreased, which possibly changed the ecological process and weakened the resistance of MEBF to biological invasion. The positive associations in and between vertical layers in the plant community were also weakened. In addition, we found that Aidia canthioides, Syzygium rehderianum, and Ormosia glaberrima had significantly positive associations with many species consistently from 1992 to 2015. This indicates that they could be of importance to community assembly and, potentially to restoration and afforestation in this area.