Understanding the trend of vegetation change and its reaction to climate variation is important for revealing the mechanism of ecosystem behavior. However, current research rarely systematically analyzes the time effects of climate variation on vegetation dynamics (time-lag and time-accumulation effects), especially in arid and semi-arid mountainous terrain. The typical mountainous terrain—the Qilian Mountains was taken as the study area, and the spatiotemporal changes and vertical zonality distributions of the normalized vegetation index (NDVI) were explored. This study explored the time-lag and time-accumulation effects of the NDVI response to climate factors (precipitation, temperature), identified the main controlling factors that influence the variation of NDVI. The results show that in the growing season from 2000 to 2019, the NDVI represented an overall upward trend, especially in the northwest, and the growth rate of NDVI at low-altitude was greater. The time-accumulation effect of precipitation has an obvious effect on vegetation, especially on deserta and meadow; and the time-lag and time-accumulation effects of temperature have an obvious influence. Regarding the climate-vegetation response mechanism, this study finds that considering the optimal time effect is of great significance. In addition, compared with precipitation, the temperature has a more significant promotion effect on vegetation growth in the Qilian Mountains. The above results indicate that when the existing climate models study vegetation-climate interactions, considering the time effects of vegetation response to climate is of great significance for accurately monitoring vegetation dynamics under environmental changes.

了解植被变化趋势及其对气候变化的反应对于揭示生态系统行为机制具有重要意义。然而，目前的研究很少系统地分析气候变化对植被动态的时间效应（时滞和时间累积效应），尤其是在干旱和半干旱山区。以典型的山地——祁连山为研究区，探讨了归一化植被指数（NDVI）的时空变化和垂直带状分布。本研究探讨了NDVI响应对气候因子（降水、温度）的时滞和时间累积效应，确定了影响NDVI变化的主要控制因素。结果表明，在 2000 年至 2019 年的生长季，NDVI 总体呈上升趋势，尤其是在西北地区，低空 NDVI 增长幅度更大。降水的时间累积效应对植被有明显的影响，尤其是沙漠和草甸；温度的时滞和时间累积效应有明显的影响。对于气候-植被响应机制，本研究发现考虑最佳时间效应具有重要意义。此外，与降水相比，气温对祁连山植被生长的促进作用更为显着。上述结果表明，现有气候模型研究植被-气候相互作用时，