为揭示海拔对青海云杉（Picea crassifolia Kom.）林林下植被多样性的影响，以祁连山东段的青海云杉林为研究对象，调查分析了5个海拔梯度下青海云杉林林下灌木层和草本层的物种组成及物种多样性特征。结果表明：祁连山东段青海云杉林林下植物共有79种，隶属于24科50属；其中，灌木植物有19种，蔷薇科（Rosaceae）种类最多；草本植物有60种，毛茛科（Ranunculaceae）种类最多。重要值分析结果显示：灌木层优势种为银露梅〔Dasiphora glabra (G. Lodd.) Sojak〕、小叶金露梅〔D. parvifolia (Fisch. ex Lehm.) Juz.〕、金露梅〔D. fruticosa (Linn.) Rydb.〕和山生柳（Salix oritrepha Schneid.），草本层优势种主要为薹草（Carex spp.）和珠芽蓼〔Bistorta vivipara (Linn.) Gray〕。青海云杉林林下灌木层的物种丰富度指数、Simpson优势度指数和Shannon-Wiener多样性指数整体随海拔升高呈先升高后降低的趋势，符合物种多样性垂直分布的“中间高度膨胀”理论；灌木植物的物种丰富度指数和Pielou均匀度指数与海拔分别呈显著（P＜0.05）正相关和负相关，而草本植物的各多样性指数与海拔均无显著（P>0.05）相关性。Srensen相似性系数分析结果显示：随海拔升高，相邻海拔梯度林地间的相似性逐渐降低，并且海拔梯度跨度越大，林地间的相似性越低。综合分析表明：祁连山东段青海云杉林林下灌木层物种多样性受海拔影响显著，而草本层物种多样性受海拔影响不明显。

To reveal the effects of altitude on diversity of vegetations under Picea crassifolia Kom. forests, P. crassifolia forests in the eastern Qilian Mountains were taken as research objects, and the species composition and species diversity characteristics of shrub and herb layers under P. crassifolia forests at 5 altitudinal gradients were investigated and analyzed. The results show that there are 79 species of understory plants in these P. crassifolia forests in the eastern Qilian Mountains, belonging to 50 genera of 24 families, in which, there are 19 species of shrub plants and Rosaceae species are the most, and there are 60 species of herb plants and Ranunculaceae species are the most. The importance value analysis result shows that the dominant species in shrub layer are Dasiphora glabra (G. Lodd.) Sojak, D. parvifolia (Fisch. ex Lehm.) Juz., D. fruticosa (Linn.) Rydb., and Salix oritrepha Schneid., and the dominant species in herb layer are mainly Carex spp. and Bistorta vivipara (Linn.) Gray. The species richness index, Simpson dominance index, and ShannonWiener diversity index of shrub layer under P. crassifolia forests show a tendency to first increase and then decrease with the increase of altitude in general, which consistent with the ‘mid-elevation bulge’ theory in the vertical distribution of species diversity; the species richness index and Pielou evenness index of shrub plants show significant (P＜0.05) positive and negative correlations with altitude, respectively, while there are no significant (P>0.05) correlations between each diversity index of herb plants and altitude. The Srensen similarity coefficient analysis result shows that with the increase of altitude, the similarity between forests at adjacent altitudinal gradients gradually decreases, and the greater the altitudinal gradient span, the less the similarity between forests. The comprehensive analysis shows that the species diversity of shrub layer under P. crassifolia forests in the eastern Qilian Mountains is significantly affected by altitude, while the species diversity of herb layer is not evidently affected.