Highland barley phenophases and parallel temperature and precipitation data at the Menyuan Agricultural Meteorological Station, Qinghai Province, from 1980 to 2015, were used to analyze the change trend of highland barley phenology and its driving factors under a climate change background in Menyuan County, Qinghai Province. The results indicated that the sowing, seedling, and jointing stage tended to be delayed, whereas the phenological period overall was advanced. Sowing stage was significantly delayed by 2.65d/10a, and the tillering and heading stage were advanced by 4.78d/10a and 2.30d/10a, respectively. The climatic factors that significantly affected the phenological periods of highland barley were temperature, precipitation, and accumulated temperature. When 0℃ accumulated temperature before sowing increased by 1℃ and precipitation increased by 1mm, sowing was delayed by 0.252d. When stable accumulated temperature increased by 1℃, the tillering stage was advanced by 0.026d, and when minimum temperature in April increased by 1℃, the heading stage advanced by 1.890d. Since the 1990s, the sowing stage delayed, the tillering stage and heading stage advanced, and the driving factors increased. The phenological period and the driving factors began to change at the same time, which indicated that the plateau of climate warming in Qinghai was the dominant factor determining the phenological changes of highland barley.