[Objective]Taxus cuspidata is a tertiary relic species and the national level endangered plants. The species composition and community structure of T. cuspidata forestand the spatial correlation between T. cuspidata and other major tree species were studied to explore the formation and maintenance mechanism of community biodiversity. [Method]According to the field protocol of the 50 hm2 plot in Panama ( Barro Colorado Island,BCI) ,a 25 hm2 plot was established in 2014 in Muling National Nature Reserve of Heilongjiang Province. All woody plants with diameter at breast height (DBH) ≥ 1 cm were mapped,tagged,and identified to species. I (DBH < 10 cm),II (10≤DBH <30 cm),III ( DBH≥ 30 cm) . [Result]In the 2014 census,we documented 57 woody species with 63 877 individuals,belonging to 38 genera and 22 families. The mean DBH of all trees was 7. 83 cm,all species were found when sampling area was set as 21 hm2 . The DBH distribution of all individuals showed a reversed“J”type. The DBH distributions of the T. cuspidata and Corylus mandshurica were approximate normal and“L”type,respectively,other major species showed reversed“J”type,including Tilia amurensis,Acer mono,Acer barbinerve,Acer tegmentosum,Betula costata,Abies nephrolepis and Pinus koraiensis. Within a scope of less than 50 m,Tilia amurensis,Acer mono,Corylus mandshurica,Acer tegmentosum, Betula costata displayed a gathered distribution,Abies nephrolepis,Acer barbinerve,T. cuspidata first displayed a gathered distribution,followed by random distribution and uniform distribution. The distribution pattern of Pinus koraiensis fluctuated between aggregate distribution and random distribution. T. cuspidata and Acer mono were negatively correlated at small spatial scales (1,3,5 m),and with the increase of spatial scale,became independent of each other,and went positively correlated when the spatial was larger than 30 m. T. cuspidata was negatively correlated with five species in different spatial scales,including Acer barbinerve,Acer tegmentosum,Betula costata,Corylus mandshurica and Pinus koraiensis. Generally. T. cuspidata was negatively correlated with Abies nephrolepis,but showing independent of each other at few scales. In contrast,T. cuspidata was independent with Tilia amurensis at most scales,and showing negative correlation at few scales. [Conclusion]T. cuspidata forest had a relatively high species richness. Sapling regeneration of most species was fairly good,but very poor for T. cuspidata. Spatial distribution of species was significantly correlated with habitat,and the species showed different habitat preferences. T. cuspidata may be a niche differentiation with some species,including Pinus koraiensis,Abies nephrolepis,Tilia amurensis,Acer tegmentosum,Corylus mandshurica,Betula costata and Acer barbinerve.%【目的】东北红豆杉系红豆杉属的第三纪孑遗的珍贵乔木，国家一级保护植物。本研究旨在分析东北红豆杉大样地的物种组成与群落结构及东北红豆杉与其他主要树种的种间空间关联性，为进一步探讨东北红豆杉林群落生物多样性的形成与群落维持机制提供依据。【方法】参照 BCI( Barro Colorado Island)中50 hm2样地的技术规范，于2014年在黑龙江省穆棱东北红豆杉国家级自然保护区建立1块25 hm2的固定监测样地，并对样地内DBH≥1 cm的木本植物进行每木调查。【结果】样地内木本植物共57种，其中乔木32种，灌木21种，藤本4种，隶属于22科38属，包括裸子植物2科4属6种、被子植物20科34属51种；所有树种的平均胸径为7.83 cm，物种丰富度为63877株，当取样面积为21 hm2时所有物种全部出现；样地内所有个体的径级分布呈倒“J”型，其中东北红豆杉的径级分布呈正态分布型，毛榛呈“L”型，其余主要树种紫椴、色木槭、簇毛槭、青楷槭、枫桦、臭冷杉和红松均呈倒“J”型；在小于50 m的尺度内，紫椴、色木槭、毛榛、青楷槭和枫桦均呈聚集分布，臭冷杉、簇毛槭、东北红豆杉均呈先聚集分布，再随机分布，后均匀分布，红松呈在聚集分布和随机分布间波动；东北红豆杉与色木槭的空间关联性在小尺度(1，3和5 m)上呈负相关，随着空间尺度增大呈相互独立，当空间尺度大于30 m时呈正相关，东北红豆杉与簇毛槭、青楷槭、枫桦、毛榛和红松的空间关联性在不同空间尺度上均呈负相关，东北红豆杉与臭冷杉在不同尺度上基本呈负相关，仅在个别尺度呈相互独立，东北红豆杉与紫椴在不同尺度上基本呈相互独立，仅个别尺度呈负相关。【结论】东北红豆杉林具有较高的物种多样性，大部分树种的更新良好，而东北红豆杉更新极差；不同物种具有不同生境偏好，物种空间分布与生境紧密关联；红松、臭冷杉、紫椴、青楷槭、毛榛、枫桦、簇毛槭与东北红豆杉可能存在生态位分化。
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