Abstract: In order to investigate the differential process of radiant heat action among various urban underlying surfaces,four types of substrates（grass,concrete,paving blocks and asphalt）were selected as research subjects,measurements were conducted on the shortwave radiation intensity reflected by different underlying surfaces,upward long-wave radiation intensity,surface heat flux intensity,air temperature,wind speed and other environmental parameters. The differences in radiant heat transfer process between the different subbedding surfaces were analyzed and compared. The results show that atmospheric inverse radiation accounts for more than 65% of the radiant heat absorbed by the underlying surfaces,and all four types of underlying surfaces release more than 75% of the heat in the form of long-wave radiation;the heat transfer between the underlying surfaces and the air is mainly carried out in the form of radiation heat transfer;the thermal stability of grass is the best in summer,and the thermal stability of concrete underlying surfaces is the worst;the thermal stability of concrete is the best in winter,and the thermal stability of paving blocks is the worst.