A calculation method of radiant time factors is presented and the method is used to calculate radiant cooling load. Based on experimental data of total heat gain and total cooling loads collected within 24-h, radiant heat gain and radiant cooling load can be calculated through convection and radiation separating,method. Transfer function is obtained and 24-term radiant time factors can be calculated by transfer function coefficients matrix. The results show that the calculation method of radiant time factors is feasible by experiment and the results provide some important information for applying radiant time factors to calculate radiant cooling load in air conditioning building. (C) 2014 Elsevier Ltd. All rights reserved.