Vegetation phenology is the most intuitive and sensitive indicator of seasonal and inter-annual variability under environment conditions.The phenology monitoring methods mainly include field observation, phenology model,digital camera and remote sensing technology.On the Tibetan Plateau,the start of growing season for alpine grassland had four viewpoints:experiencing an advancing and advancing in fluctuating trend,apostponing trend and no change,respectively.Phenology phases experience interactions with climatic factors.These factors,such as temperature,precipitation,CO_2 concentration,snow cover and extreme climate,play an important role in alpine grassland growth.Meanwhile,phenology changes at different scales and the driving factors are uncertainty.Finally,the existing problems and the future research directions were discussed.