Abstract: With the accelerating of urbanization, the impact of urban heat island effect on vegetation phenology is receiving more attention. MODIS data and products (MOD11A2, MCD12Q2, MOD13Q1) were used in combination with other related data to analyze the urban heat island effect and spatial and temporal distribution characteristics of vegetation phenology in the Urumqi-Changji, Shihezi-Manas, and Wusu-Kramay-Kuidun regions. In addition, the major urban clusters of the Tianshan Northslope Economic Belt and the relationship between them were analyzed. The results of the study show that the urban heat island intensity (UHII) was most pronounced in the Urumqi-Changji region among the three major urban agglomerations, with a range of 0.39-2.49℃. The overall performance show that the heat island intensity at night was higher than that during the day. The vegetation phenology distribution along the urban-rural gradient direction showed obvious differences. Start of growing season (SOS) was earlier, end of growing season (EOS) was later, and the vegetation growth season (GSL) was longer in urban than in suburban and rural areas. Among them, the vegetation in the Urumqi-Changji region had the earliest SOS, the latest EOS, and the longest GSL. The vegetation distribution phenology along the urban-rural gradient was significantly correlated with UHII, which showed a significant negative correlation with △SOS and a high positive correlation with △EOS and △GSL. The effect of UHII on vegetation phenology was more obvious at night. The results of this study are helpful in understanding the influence of vegetation phenology on urban heat island effect along the urban-rural gradient in the Tianshan Northslope Economic Belt and can also provide a theoretical basis and reference for improving the ecological environment of urban clusters in this economic zone.