Abstract: Based on the highland barley yield, yield composition factors and parallel climate data of the agricultural meteorological station of Menyuan County from 1980 to 2021, the Pearson correlation coefficient method, principal component analysis, and integral regression are used to analyze the relationship between the yield formation factors and yield of spring highland barley, as well as the key climatic factors and the key period of impact. The results show that the yield formation of highland barley is closely related to the growth height, grain number per ear, 1000-grain weight and stem weight during the jointing stage. The yield formation is also closely connected with the plant density of the jointing stage. During the whole growing season, the temperature in May, July and April has a positive effect on the yield of highland barley, while the temperature in June, March and August has a negative effect. May to July is the key period for temperature to affect the yield, that is, the emergence - flowering stage.April is the key period for precipitation to affect the yield, that is, the seed-emergence period. The key stage of sunshine hours affecting the yield of highland barley is the jointing stage. The key factor restricting the formation of local highland barley yield is temperature.