To investigate the niche and interspecific associations of the dominant species in different forest types within the main distribution area of the endangered plant Calycanthus chinensis, three typical forest types (deciduous-evergreen broadleaf mixed forest, Chinese fir forests and moso bamboo forests) in Dalei Mountain, Tiantai County, Zhejiang Province, were studied from September to October 2023. Levins and Shannon-Wiener niche breadth index, Pianka niche overlap index, variance ratio (VR), χ2 test were applied to quantify the niche characteristics and interspecific association of the top 20 dominant species in the tree and shrub layers of three forest types. The results showed that: (1) A total of 156 plant species belonging to 64 families and 119 genera were recorded in the tree and shrub layers across the three forest types: 109 species in deciduous-evergreen broadleaf mixed forest, 92 in Chinese fir forest, and 114 in moso bamboo forest. (2) C. chinensis was mainly found in the shrub layer across all three types of forests. Within this layer, it showed higher importance values and a wider niche breadth than in the tree layer of the same communities. Its niche breadth was greatest in the deciduous-evergreen broadleaf mixed forest and smallest in the moso bamboo forest, suggesting that it holds a dominant competitive role in resource use within the deciduous-evergreen broadleaf mixed forest community. (3) Among the 190 species pairs formed by dominant species in shrub layers in deciduous-evergreen broadleaf mixed forest, Chinese fir forests and moso bamboo forests, significant niche overlap was detected in 127, 103 and 135 species pairs, respectively. Among the species pairs formed by C. chinensis and the other 19 dominant species, there were 19, 17, and 11 pairs showing significant niche overlap respectively, exhibiting a relatively high degree of overlap. (4) The overall interspecific associations in the shrub layers of all three forest types exhibited significant positive association, suggesting high community stability. (5) The χ2 test showed that most species pairs in the shrub layers had nonsignificant associations, indicating weak interspecific association and independent distribution patterns. The deciduous-evergreen broadleaf mixed forest contained the highest number of positive associations, favoring species coexistence. Based on the above analysis, it can be inferred that C. chinensis adapts to its environment through mechanisms such as vertical stratification, phenological niche differentiation, and habitat selection. Among these, the interspecific relationships within deciduous-evergreen broadleaf mixed forests exhibit a higher degree of coordination, contributing to enhanced overall community stability. This community type offers a more stable environment for population regeneration of C. chinensis.