By analyzing and making a comparison between five methods of geometrical information gathering in existing buildings, this paper shows that the method of geometrical information gathering in buildings based on the 3-dimensional (3D) geometrical reconstruction is suitable for the evaluation of existing building applied photovoltaic (BAPV) potential. Then, it tested the accuracy of different ways of image acquisition by using low-rise, multi-storey and high-rise buildings as experimental subjects. Moreover, based on a building in Tianjin, an evaluation method is proposed to verify the feasibility and accuracy of the method. Finally, we developed a reliably and feasibly evaluation method to evaluate the BAPV potential. (C) 2016 Elsevier B.V. All rights reserved.