[Objective] Investigate the comprehensive effects of four different intercropping patterns of perennial forage grasses on growth, photosynthetic characteristics, and soil moisture in the Loess Plateau, screen the optimal intercropping system, and provide theoretical support for establishing high-yield, high-efficiency, and sustainable artificial grasslands in the Loess Plateau. [Methods]In this study, four perennial forage grasses, namely Medicago sativa (M), Bromus inermis (W), Elymus dahuricus (P), and Astragalus adsurgens (S), as the research subjects, four monoculture, four two-species, two three-species, and one four-species intercropping were set up to analyze the growth, photosynthetic, and water use characteristics of the forages under different mixture patterns. [Results] The total relative yield of all intercropping treatments was greater than 1. The intercropping treatment of Medicago sativa and Bromus inermis achieved a total relative yield of 2.08, increasing the biomass of Bromus inermis to 279.1% of that in monoculture and that of Medicago sativa to 132.4% of that in monoculture. The intercropping treatment of Medicago sativa and Bromus inermis significantly increased the net photosynthetic rate and transpiration rate of Medicago sativa (P<0.05), had no significant effect on the net photosynthetic rate of Bromus inermis, but significantly increased its leaf water use efficiency (P<0.05). The intercropping of Medicago sativa and Bromus inermis increased the water content of deep soil. Entropy-Weighted TOPSIS evaluation revealed that the Medicago sativa and Bromus inermis intercropping has the best comprehensive effect in terms of forage yield, growth physiological characteristics, water and soil resource utilization efficiency and soil water storage capacity, whereas the comprehensive effect of gramineous monoculture is the worst. [Conclusion] This study demonstrates that reasonable intercropping configurations can optimize vertical soil moisture distribution and enhance forage net photosynthetic rate, thereby improving system productivity and water utilization. The Medicago sativa and Bromus inermis intercropping system effectively enhances both production capacity and water use efficiency, providing valuable practical guidance for optimizing forage intercropping systems in semi-arid regions of the Loess Plateau.