The purpose of this research was to explore an irrigation pattern taking into account the yield and quality of forage in the alpine desert area, and to promote the application of micro-sprinkler irrigation and regulated deficit irrigation in artificial grassland production. A field experiment was conducted to compare and analyze the effect of 2 cropping patterns and 7 irrigation patterns on forage yield, quality (stem-leaf ratio, crude protein content and yield, acid detergent fiber content, and neutral detergent fiber content) and water use efficiency. The 2 cropping patterns were mono-sowing oats and mixed sowing of oats and peas, and the 7 irrigation patterns were mild water deficit at jointing stage (65%~75%), moderate water deficit at jointing stage (55%~65%), severe water deficit at jointing stage (45%~55%), mild water deficit at flowering stage (65%~75%), moderate water deficit at flowering stage (55%~65%), severe water deficit at flowering stage (45%~55%), and full irrigation during the whole growth stages (75%~85%). In addition, the methods of analytic hierarchy process and entropy weight were used to empower the multiple indicators of forage, and an evaluation system was constructed based on the TOPSIS model to obtain the optimal irrigation pattern. The results showed that: (1) With the increasing of water deficit, the forage yield showed a decreasing trend. Under the same irrigation condition, the forage yields of mixed sowing of oats and peas (7 811.1~14 490.1 kg/hm²) were higher than those of mono-sowing oats (7 022.3~12 242.7 kg/hm²). (2) Under the same cropping pattern, the contents of NDF and ADF decreased first and then increased with the increasing of irrigation deficit. However, the content and yield of crude protein, WUE, and IWUE increased first and then decreased with the increasing of irrigation deficit. (3) The comprehensive evaluation showed that mixed sowing of oats and peas with full irrigation at jointing stage and moderate water deficit at flowering stage could achieve better water-saving, yield-increasing, and quality-improving effects (forage yield, crude protein content, WUE, and IWUE were 14 330.2 kg/hm², 10.66%, 31.49 kg/(hm²·mm), and 80.96 kg/(hm²·mm), respectively). It was a suitable production management pattern of artificial grassland using micro-sprinkler irrigation in alpine desert grassland.