Wuhan City was used to accurately evaluate the differentiation characteristics of canopy heat island intensity in highly complex megacity. A calculation method for canopy urban heat island intensity （CUHII） considering spatial differences in different urban areas was proposed. The characteristics of urban heat islands under different algorithms were studied with combining traditional algorithms based on the “urban suburban” dichotomy. Results showed that each area consistently exhibited urban heat island phenomenon under traditional algorithms， and the daily variation curve of CUHII was highly consistent. On the contrary， there was a significant difference in the daily variation of CUHII among different areas in the regional algorithm， and the Wuchang district with multiple large ecological spaces exhibited a sustained cold island phenomenon during the daytime. In addition， traditional algorithms identified cold and heat island centers that are relatively small and distributed around the periphery of the central urban area， while regional algorithms identified heat island centers that cover high-density development areas in the middle of the urban area in a belt shape， and the cold island centers are adjacent to large natural lakes in the Wuchang district. It is indicated that the algorithm proposed weakens the interference of uneven development of urban areas on the assessment of canopy heat island， which is conducive to in-depth mining of heat island characteristics and more accurate identification of areas that need priority intervention in urban thermal environment.