The species of Smilax grabra Wall. ex. Roxb. belongs to Smilacaceae family that is a medecinal plant common used by local people. This species is commonly distributed in the north moutainous to middle areas of Vietnam. Over exploitation has lead to this species faced with endangerment. This study focus on evaluation of the ecological characteristics and distribution condition for Smilax grabra in Dinh Hoa district, Thai Nguyen province. The result found that 4 plants have the same remedy and usage: Smilax glabra Wall. ex. Roxb., Smilax bracteata Prest., Smilax lancaefolia Roxb. and Smilax riparia AD.C. Ecological characteristics of the Smilax grabra were studied. Correlation between 27 ecological environmental factors with species distribution were determined. Sedges and shrubs, trees, green cover and all vascular species were grouped for analysis of the correlation with species distribution. This study is a fundamental approach for biodiversity conservation and interaction between vegetation with ecological conditions. Study on correlation between species and soil, other ecological- environmental factors should be more focused and implemented in other species.