Pervious concrete has good permeability and moisture adjustment properties due to its rich pore structure. It can not only penetrate rainfall to reduce surface runoff, but also retain a certain amount of water inside then via evaporation to decrease surface temperature. In order to improve the water retention of pervious concrete and prolong its cooling effect, this study introduced a modified method of incorporating biochar produced by pyrolyzing agricultural wastes into pervious concrete as hygroscopic filler. The effects of biochar on the mechanical properties of pervious concrete were analyzed, then the thermophysical properties, water absorption properties and evaporative cooling performance of biochar-modified pervious concrete with the optimum replacement rate were studied. The results show that the carbonaceous particles after grinding could fully exert the filling and internal curing effects when the replacement rate was less than 5.0%, and effectively improve the mechanical strength of pervious concrete. It was found that the biochar addition had little impact on the emissivity of pervious concrete, while significantly reduced the reflectivity and thermal conductivity. Contributing to the abundant micro-pores and higher specific surface area of biochar particles, it could improve capillary water absorption and water storage ability of pervious concrete. During the evaporation process, the water absorption increment could effectively reduce surface temperature of 3-6 ℃ and maintain evaporation cooling effect for 14-18 h.