Abstract: Augmented Reality (AR) is a new technology for a wide range of applications, which involves many areas of social life, such as medicine, military, transportation, education, entertainment, industrial machinery, landscape planning, cultural relic protection, etc., and has also been applied for underwater engineering at present. AR has been successfully applied for underwater positioning and survey in ocean engineering for the first time in China. An ROV (remotely operated vehicle) is equipped as a carrier with a 3D camera and relevant underwater sensors. Through the unique AR software, the structural 3D model, virtual markers, and virtual measurement tools could be superimposed onto the video images transmitted from underwater to the ground surface, with which the real-time communication between the operators on the ground and the real underwater environment and real-time monitoring on position and attitude of underwater structures could be realized. The application of AR in underwater positioning and survey breaks by traditional operation method showed high precision, high efficiency, low cost, non-contact, and real-time measurement. In addition, the ROV does not need to cling to the structure, the software is easy to operate, the measurement data are reliable and real-time display, which could effectively reduce the operation risk of ROV and improve the working efficiency.