With the rapid growth of DLP projection technology in the late years, DLP projection technology has been gradually applied to numerous disciplines. Phaseshifting method often works with DLP projection technology due to its flexibility and high precision. As a nonlinear instrument, the projector could hardly project ideal fringe patterns, and could hardly achieve high projection speed. The binary defocusing provides a new solution for high speed and high precision measurement. This paper analyses the current status and development trend of 3D shape measurement by using projector defocusing at home and aboard. A survey is presented for the working principle of DMD, phaseshifting algorithms, unwrappingalgorithms, error compensation methods, the modulating methods for fringe pattern, the calibration methods and some of the details about projector defocusing further. This work can provide references for the researchers engaged in 3D shape measurement by using projector defocusing.