Abstract: In this dissertation, the author adopted the normalized differential vegetation index (NDVI) and meteorological data sets of 1982-2016 from Qinghai province, China to analyze the effects of daytime and nighttime warming asymmetric changes in spring, summer and autumn on vegetation activities during the growing season period according to the copula function theory based on Markov Chain Monte Carlo (MCMC). The main conclusions were as follows: (1) in the past 35 years, the seasonal daytime and nighttime warming trend of Qinghai plateau was remarkable in the growing season. The rate of daytime and nighttime warming was asymmetric. In spring, the warming rate in the daytime was faster than that at nighttime. However, in summer and autumn, the warming rate at nighttime was greater than that in the daytime. The diurnal temperature difference shows seasonal differences, with large fluctuations in spring, summer and autumn. The diurnal temperature difference presents an upward trend in spring, while it displays the opposite rule in summer and autumn. (2) The asymmetry of daytime and nighttime warming had great influence on vegetation, showing a seasonal difference. And the diurnal and nocturnal warming had the greatest influence on vegetation in autumn, followed by summer and the smallest in spring. The influence of daytime warming on vegetation was stronger than that of nighttime warming. (3) The joint probability distribution functions of daytime and nighttime warming and NDVI on the three seasons of plateau showed certain laws. If the daytime and nighttime warming was constant, then the greater the NDVI, the greater the joint probability would be; or if the NDVI was fixed, the greater the daytime and nighttime warming, the greater the joint probability would be. These phenomena indicated that the daytime and nighttime warming would have little effect on NDVI when they reached their minimum values. However, when the daytime and nighttime warming reached their maximum values, they would have remarkable effect on NDVI. (4) The smaller the return period was, the larger the value range of the diurnal and nocturnal warming and the NDVI were. This phenomenon indicated that the NDVI would be more likely to have a smaller return period when the diurnal and nocturnal warming was constant. The larger the diurnal and nocturnal warming, the greater the return period was, which indicated that the inhibition phenomenon of plant growth would have a higher probability to happen when the diurnal and nocturnal warming exceeded a certain threshold. This research can be helpful to deeply understanding the effects of daytime and nighttime warming asymmetry on the vegetation dynamics in typical plateau climatic region under the background of global climate change, thus better explaining the response and feedback of plateau terrestrial ecosystems to global climate change.