Taking Populus euphratica in Ejina as the research object, we analyzed the characteristics of leaf color parameters, pigment contents of P. euphratica and meteorological conditions in different periods. The main influencing factors of leaf discoloration of P. euphratica were explored, which laid a research basis for leaf senescence of P. euphratica and meteorological service of yellow leaf phenology landscape in Ejina in autumn. The results showed that: (1) the leaf color parameters L^*, a^* and C^* of P. euphratica showed a gradually rising tendency, the b^* and h values increased first and then decreased. The changes of leaf color showed green, light yellow, golden and orange in leaf color changing process. (2) During the discoloration period of P. euphratica, the content of leaf chlorophyll in leaves decreased significantly, while the lutein and carotenoids contents increased slowly first and then decreased slightly, the content of anthocyanin had little change, and the content of soluble sugar also increased first and then decreased. The ratio of total chlorophyll to carotenoids decreased by 97.5% at the end of discoloration compared with the initial stage. (3) In the same period of leaf discoloration of P. euphratica, the temperature gradually decreased, and the daily temperature range kept relatively stable at about 14 ℃, the direct radiation gradually decreased, and the average relative humidity first increased and then decreased, but the overall performance was an increasing trend. The evaporation decreased gradually as a whole. (4) During the color changing period, leaf color parameters L^*, a^*, b^*, C^* were significantly negatively correlated with chlorophyll a, chlorophyll b, total chlorophyll contents and the ratio of chlorophyll to carotenoids (P<0.01). The maximum temperature, minimum temperature and average temperature showed significant negative correlation with leaf color parameters L^*, a^*, b^*, C^* (P<0.05), while they showed significant or extremely significant positive correlation with chlorophyll a, chlorophyll b, total chlorophyll contents and the ratio of chlorophyll to carotenoid. Air relative humidity showed a significant or extremely significant positive correlation with lutein and carotenoid. The study revealed that the leaves landscape of P. euphratica in Ejina gradually showed light to dark yellow in the process of senescence, which was the result of large and rapid decomposition of chlorophyll and relative increase of carotenoid content. Temperature was the main limiting meteorological factor affected the senescence and etiolation of P. euphratica leaves. Chlorophyll decomposition was accelerated at low temperature, and higher air humidity was conducive to keeping carotenoid content remain stable and maintaining a longer viewer period of yellow leaf landscape.