Abstract: Ultra-thin 321 stainless steel strips play a crucial role in electronic products and various precision instruments and equipment. In this study, a self-developed metal micro-forming rolling mill was adopted to investigate the variation laws of rolling force and finish rolling thickness during the asynchronous rolling of ultra-thin 321 stainless steel strips by adjusting the speed ratio and front-and-back tension. The results show that increasing the speed ratio can effectively reduce the rolling force and improve the thinning capacity of the rolling mill. Meanwhile, electrochemical experiments were conducted to analyze the effect of cold rolling reduction on the corrosion performance of ultra-thin 321 stainless steel strips. It is found that with the increase of rolling reduction, the corrosion rate of the ultra-thin strips accelerates and the corrosion resistance decreases. The analysis results of XRD patterns indicate that the austenite content of ultra-thin 321 stainless steel strips decreases and the martensite content increases with the increase of rolling reduction, which leads to the deterioration of its corrosion performance.