落叶松林是我国东北林区最为重要的林型之一，对维持东北地区森林生态系统的稳定具有重要作用。以东北森林带落叶松林固定样地木本植物为研究对象，通过野外样方调查、多样性及空间结构指标计算，并结合方差分解分析和冗余分析，探究落叶松林树种多样特征及影响因素。结果表明，东北地区落叶松林树种丰富度均值为10.75，Simpson指数为0.72，Shannon-Wiener指数为1.69，Pielou均匀度指数为0.76。林分树种混交度均值为0.57，林分处于中度混交状态；角尺度为0.54，林分为聚集分布；胸径大小比数为0.51，林分生长为中庸状态。林分空间结构特征和地理气候共同解释35.9%的树种多样性变化，其次是空间结构特征，解释率为29.2%。简单效应分析显示混交度M_i 、纬度（Latitude）、年均温（MAT）和年降水（MAP）等空间结构和地理气候指标是树种多样性变化的主要影响因子。研究结果将为东北地区落叶松林经营策略的制定提供理论依据和数据支撑。

The Larix gmelinii forests is one of the most important forest types in Northeast China， playing a crucial role in maintaining the stability of the forest ecosystem in the region. The woody plants in the permanent plot of Larix gmelinii forests in Northeast China were taken as the research object. Through field plot investigation， diversity index and spatial structure characteristics calculation， combined with variance partitioning analysis and redundancy analysis， this study explored the characteristics and influencing factors of tree species diversity in Larix gmelinii forests. The results showed that the average tree species richness of Larix gmelinii forests was 10.75 in Northeast China， Simpson index was 0.72， Shannon-Wiener index was 1.69， and Pielou evenness index was 0.76. The average mingling intensity was 0.57， indicating that the forest stands were moderately mixed. The uniform angle index was 0.54， and the forest stands were clustered. The breast diameter dominance was 0.51， indicating that the forest growth was in a moderate state. The spatial structure characteristics of forest stands and geoclimatic conditions jointly explained 35.9% of the changes in tree species diversity， followed by spatial structure characteristics， with an explanatory rate of 29.2%. Simple term effects showed that spatial structure and geoclimatic indicators such as mingling intensity， latitude， annual mean temperature， and annual mean precipitation were the main influencing factors of tree species diversity changes. The research results will provide theoretical basis and data support for the formulation of management strategies for Larix gmelinii forests in Northeast China.