Heat source forms influence the cooling capacity of the radiant cooling terminal. This paper introduces three different forms of heat sources commonly used in the performance test of radiant cooling terminal: internal heat source, external heat source A and B. To external heat source A, the heat is supplied by one internal wall, while to external heat source B, the heat is supplied by four internal walls and the floor. Simulations of the cooling capacity of radiant cooling terminal under the conditions of different heat sources were conducted by establishing heat transfer models, respectively. The terminal cooling capacity under the conditions of external heat sources A and B can be enhanced by 10% and 13%, respectively, compared with that under the condition of internal heat source. The experimental research confirmed the accuracy of heat transfer models. Causes and influencing factors of terminal cooling performance discrepancy under the conditions of different heat sources were analyzed by using the heat transfer models. Through the analysis of the radiation proportion and the shape of the room under different heat sources, internal heat source is suggested in the testing of the terminal cooling performance. (C) 2013 Elsevier B.V. All rights reserved.