对拉矫开始时带材延伸率的变化情况进行了分析，提出了延伸率过渡阶段和延伸率稳定阶段的概念，并指出在过渡阶段带材延伸率是变化的．根据过渡阶段带材延伸率变化的事实，分析了采用延伸率直接控制方式的拉矫机在起、制动阶段带材张力波动以及带材和张力辊之间打滑的原因，并提出了延伸率控制应遵循的原则． The change of the strip elongation at the beginning of straightening is analyzed. The concept of the transitional phase of elongation and the stable phase of elongation are put forward. It is also pointed out that the elongation of strip changes during the transitional phase. According to the fact that the strip elongation changes during the transitional period, the reasons for the strip tension fluctuation and the slippage between the strip and the tension roller during the starting and braking stages are analyzed. The results show that the elongation Control should follow the principle.