The defect of titanium alloy materials has great harm, so its health status monitoring must be carried out. Laser ultrasound detecting technology has many advantages, such as noncontact, quick and high efficiency. It can be satisfied with the realtime health monitoring of titanium alloy structure. In this paper, the mechanism of laser thermoelastically generated ultrasound stress is studied. A noncontact twodimensional scanning laser ultrasound detecting system is set up based on analyzing the detection efficiency of onedimensional scanning laser ultrasound. The experimental results show that the proposed laser ultrasound detection system can be used for the realtime and online health detecting of titanium alloy structure in effect. It can realize two directions scanning and the detecting efficiency is improved by 50% than that of the onedimensional scanning under the same conditions. The experimental system is simple and is easy to realize the complete noncontact detection. The realtime and online detection of titanium alloy structure in the engineering practice can be realized and the defect location detection can also be carried out by using the proposed method in this work.