A new general modeling method for bridge based on the OpenFlight model is proposed by analyzing and simplifying the structure of bridge, making the girder-type bridge, suspension bridge, arch bridge and cable bridge a general model structure. Aiming at heat characteristics of box girder, cable, railing and other typical part of bridge, the computational model for infrared radiation characteristics is built by considering a variety of natural factors, which can be simulated through image gray information. Moreover, a general software system is developed. Experimental results show that the method can effectively simulate the infrared radiation characteristics of bridge at any time, any geographical position and any meteorological environment.