In order to reveal the variable character of plant specific leaf areas and its correlation with leaf shape in karst region,the ratio of leaf length to leaf width(LL/LW),leaf thickness(LT)and specific leaf area(SLA)and its relationship of the leaves of Cyclobalanopsis glauca—Pteroceltis tatarinowii community in northern Guangxi were investigated.The results showed that the LL/LT and LT of evergreen species were significantly higher than that of the deciduous trees,SLA of evergreen species was significantly lower than that of the deciduous trees.And LL/LW was significantly different between the arbors and shrubs,while SLA and LT were not significantly different.While,the coefficient of correlation between LT and SLA was larger than that of between LL/LW and SLA,and LT had larger impact on SLA than LL/LW.Furthermore,LT significantly affected SLA in this study.Previous researches showed that the index of SLA was the indicator measuring the ability of capturing the sun's energy for leaves.The thicker leaves were,the larger impacted on ability of obtaining sunlight.Therefore,it would lead to reduce the efficiency of photosynthesis.