In the three-dimensional measurement methods based on fringe projection, circular sinusoidal fringes have higher phase sensitivity than linear fringes. Therefore, a coaxial three-dimensional measurement method of circular fringe projection is proposed, which is based on the geometric relationship of divergent projection rays. Specifically, the fringes on the object surface are changed by the movement of the projector along the optical axis, the charge-coupled device (CCD) is employed to collect the corresponding fringe patterns, and different phase fields are calculated from these fringe patterns. The constraints between phase information and height of the object are established by the use of the change in projection rays caused by the movement of the projector. In this way, the height information of the object surface can be reconstructed without obtaining complex system parameters, and the problems of shadow and occlusion can be reduced in the measurement. Simulations and experimental results verify the effectiveness and practicability of the proposed method.