The inner surface profile of capsule,which is one of the essential parameters of laser nuclear fusion capsule, needs to be measured precisely. In this paper, the basic measurement principle of the capsule's inner surface profile, which is based on the white light confocal spectrum and precision air flotation bearing, is analyzed firstly and the corresponding measuring method is presented.Then, the experimental apparatus applied to measure the inner surface profile of capsule is developed, and an auxiliary aligning method based on optical image is proposed. The precise measurement of the inner surface profile of capsule is achieved and the accurate inner surface profile curve of capsule is obtained. Finally, the reliability of measured data is verified experimentally and the measuring uncertainty is analyzed. The experimental results illustrate that the inner surface profile of capsule can be measured accurately using white light confocal spectrum and the measuring uncertainty is less than 0.1 μm.