Abstract: The relationship between leaf size and twig size reflects the relationship between plant xylem and its supported photosynthesis area allocation ratio, and the variation of the relationship between leaf and twig growth reflects the plant adaptation mode to heterogeneous environment. By using the ArcGISestablished regional digital elevation model (DEM) for a alpine grassland on the northern slope of Qilian Mountains, Northwest China, and by abstracting the slope aspect data of the study area, this paper studied the relationship between the leaf and twig growth of Stellera chamaejasme population at different slope aspects with the method of standardized major axis estimation (SMA). With the slope aspect changed from south  to east, west, and north, the leaf area, leaf number, and twig length of the S. chamaejasme all presented an increasing trend. On all slope aspects, the leaf number, leaf area, and twig length existed allometric relationship, and the growth speed of twig length was greater than that of leaf number and leaf area. With the slope aspect changed from north to east, west, and south, the allometric slope of leaf number and twig length increased, but that of leaf area and twig length decreased. Habitat had significant effects on the leaf and twig growth of S. chamaejasme. Northern slope had more suitable habitat condition for S. chamaejasme growth, while southern slope made the twig and leaf of S. chamaejasme become smaller, and made the twigs per unit length support more leaves due to the soil moisture shortage.