The analysis of time-varying temperature field of a composite concrete-steel deck plate under strong solar radiation is carried out in this study. By assuming the temperature distribution along the bridge longitudinal direction is basically constant, one typical segment of the deck plate is investigated. Two-dimensional heat transfer models are utilized to determine the time-dependent temperature distribution of deck plate, deck trough and deck pavement of the bridge. A modified solar radiation model is utilized to predict the variation of solar radiation in a whole day. A thermodynamic model is established and a transient heat transfer analysis is conducted to predict the time-varying temperature distribution of the deck plate at different time. The measured ambient temperature data are used as thermal boundary conditions during the numerical analysis. The made observations demonstrate that the simulated temperature variation of the deck plate based on the modified solar radiation model agrees well with measurement results, as compared with those obtained from the traditional solar radiation model..