Abstract: Based on the observation data of radiation and heat flux during summer in Fengxian,a suburban area in Shanghai,Surface Urban Energy and Water Balance Scheme(SUEWS)and its sensitivity to surface cover and human activities were evaluated.The results indicated that the model can well reproduce the diurnal variation of radiation flux,and can simulate the diurnal variation and magnitude of sensible heat flux and latent heat flux well.By comparing the average Bowen ratio of dry and wet months in summer,it is found that the Bowen ratio of dry months(0.74)is close to twice that of wet months(0.40),indicating that air humidity has a significant impact on heat fluxes.The sensitivity tests of several groups of underlying surface coverage show that compared with trees,sensible heat flux and latent heat flux simulated by SUEWS are more sensitive to grass area.When the natural surface coverage is constant,the Bowen ratio decreases significantly with the increase in grass area.When the population density increases,the simulated anthropogenic heat flux significantly increases,resulting in a significant increase in the simulated sensible heat flux and Bowen ratio.