Using satellite imaging of the Earth at night, we quantitatively assess the rapid growth of urban areas and investigate its impact on long-term surface warming at 214 medium and large cities over eastern China. Urban growth intensity is measured using the size of the area experiencing fast night-time light increase and the distance to temperature-observation sites. Surface warming, related closely to city size, also exhibits a strong association with urban growth. A rapid increase of surface temperature is observed mainly for cities undergoing rapid urbanization (RU). Such a relation is evident over Central, South, and Northwest China, but it is weak over Northeast China, implying regional variation of temperature responses to urban growth. Satellite-derived land-surface temperature analysis suggests that cities experiencing RU are more subject to the effects of urban heat island expansion, which explains the variations of warming rate among cities within the same region. These results underscore that surface warming induced by RU might be an important component of urban climate change in eastern China.