Global climate change has intensified extreme heat events, posing critical challenges to urban sustainability. While existing research has addressed thermal inequity among vulnerable populations, outdoor delivery workers remain critically understudied. This study investigates the relationship between heat exposure and urban built environment across two scenarios (general vs. high-frequency delivery streets) in Tianhe District, Guangzhou, using multiple linear regression. Key findings reveal: (a). High-frequency delivery streets exhibit 2.42 ℃ higher temperatures than the district average, with 66.51% of which overlap with high-temperature streets, indicating severe heat exposure faced by riders. (b). General streets show a single-factor dominant pattern (NDVI contributing 53.28%), whereas high-frequency delivery streets exhibit dominant multifactorial pattern (NDVI: 25.50%, WIC: 26.27%, LUD: 23.72%). The paper concludes dominant factors change due to spatial functional differentiation, human activities, and occupational behavioral adaptations. Our findings offer new insights for urban microclimate management and promote environmental justice for delivery riders.