We selected Artemisia ordosica as the donator species, which is an endemic plant in the desert and semi-desert regions of China. Furthermore, we selected Agriophyllum squarrosum, Corispermum hyssopifolium, Astragalus melilotoides, and Setaria viridis as the receptor species. To find suitable associated herb species, which can co-occur, we compared the different effects of the aqueous extracts of all A. ordosica tissues (root, stem, leaf, and seed) on receptor plants, including seed germination, seedling growth, and root absorption of NH₄⁺ and K⁺. The results showed that A. ordosica aqueous extracts produced significant allelopathy effect on seed germination and seedling growth of the four receptor plants. The extracts caused inhibitory effects on A. squarrosum, C. hyssopifolium, and A. melilotoides, but S. viridis was promoted. Extracts of different parts of A. ordosica exerted different allelopathic effects on the four herbs. Root extracts had the strongest allelopathic effects on A. squarrosum, C. hyssopifolium, and S. viridis, and stem extracts had the strongest inhibitory effects on A. melilotoides. The sensitivity of different plant species and developmental stages to allelopathic effects varied. A. squarrosum was the most inhibited and followed by C. hyssopifolium and A. melilotoides of the four receptor plants. With increasing concentration of A. ordosica extracts, seed germination and seedling growth significantly decreased. Conversely, S. viridis had a certain degree of A. ordosica extract resistance and was promoted. The extracts of A. ordosica had the strongest influence on root length, followed by seed germination, shoot height, and seedling dry mass, and significantly decreased the root absorption of NH₄⁺ and K⁺ in A. squarrosum, C. hyssopifolium, and A. melilotoides, but enhanced the root uptake of NH₄⁺ and K⁺ in S. viridis. Our finding indicated that rain eluviation was one of the means by which A. ordosica released allelochemicals. Allelopathy plays an important role in A. ordosica invasion and might be responsible to the formation of mono-dominant communities.