The present work mainly discussed the development trend of additive manufacturing ( AM) technologies for titanium alloy,as well as the difficulties and research trends of nondestructive testing (NDT) of AM parts,especially for pore defects.The research progress of NDT technology for pore-type defects was introduced,including offline NDT technology,indirect NDT based on feature monitoring and online NDT technology.Then,the latest progress in laser ultrasonic testing technology for porosity in AM metal was reported.At last,the future research directions and suggestions for laser ultrasonic online NDT of metal additive manufacturing parts were shown.