Alpine meadows are mostly distributed in mountains. Changes in the mountain landform cause changes in distribution of soil moisture and temperature as well as plant species, which influence primary production of the ecosystem. To reveal the relationship between non-ecological factors (soil moisture and soil temperature), species diversity (richness, abundance, evenness, and dominance), and primary productivity in an alpine meadow ecosystem, we investigated plant community structure and soil moisture and temperature in 189 sampling sites on lowland (bottom land), shadow aspect, ridge, and sunny aspect along three elevation gradients on a hill in the Qilian Mountains in Tianzhu County in northeastern Tibetan Plateau. Linear regression was used to analyze the relationships between soil moisture, soil temperature, species diversity, and primary productivity. When the hill was treated as a single unit, primary productivity only increased significantly with increasing species abundance (R²=0.07 P=0.01). There were different effects of species diversity on primary productivity based on the hill aspect:On the shadow aspect, primary productivity had a positive linear correlation with species richness; On the ridge, primary productivity had a positive linear correlation with soil moisture that significantly increased with species richness; On the sunny aspect, primary productivity had a positive linear correlation with species abundance; and on bottom land, primary productivity had a positive linear correlation with species evenness. Primary productivity only increased significantly with increasing species abundance and richness in the low-elevation plots. In conclusion, the slope aspect had a greater effect on the relationships between soil moisture, soil temperature, species diversity, and primary productivity than did elevation in the alpine meadow and that the effect of species diversity on primary productivity was greater than that of soil moisture and temperature. We suggest that the hill aspect should be the primary consideration, instead of elevation, in grassland production and ecological management assessments in alpine meadow ecosystems.