Abstract: Process characteristics, system composition of the wire arc additive manufacturing(WAAM), as well as physical processes that occurred in WAAM were introduced. The research status of WAAM was mainly discussed from four aspects, the development of additive equipment system, process inspection and control, microstructure performance and defects and forming process factors. Current research hotspot was to investigate on the microstructure and mechanical properties of the formed parts, and analyze defects such as residual stress, deformation, porosity, cracking and delamination. Another research hotspot was to investigate on key factors affecting the precision and surface morphology for different material systems and different welding process. The application of WAAM at home and abroad was also briefly introduced in the paper. It was founded in the review that the basic research of WAAM was relatively weak, especially that the heat and mass transfer mechanism was very lacking. It was urgent to promote the development of this technology by accurate and systematic theoretical and simulation research,which might provide refined guidance for WAAM.