Spring-back is an important factor which effecting the precision of tube forming.By researched on the tube forming control technology,and based on the fundamental of single-point forming principle,a single point fitting incremental forming method was proposed on tube forming.A coordinate system of tube fit forming was established,then its based on multi-axis numerical control(NC)system was designed.By non-contacted measuring of the distance error before and after forming,and transforming to get the actual plastic forming angle,the spring-back of single-point forming was detected in real time,and the forming angle was compensated and corrected during next forming process,then the closed loop control in incremental tube fit forming was implemented.The experiment shows the system can measure the springback effectively,and warrant repeatability accuracy and adaptability of the tube forming process.