Driving unit chain concept was put forward to explore the shield refinement tunneling technology in complex and changeable strata and environment instead of the traditional control method according to the interval length. Then four key elements of driving unit were defined including the connotation, the principle of division, the steps and the application conditions. Subsequently, a new method of driving unit control in construction of shield metro tunnel was established, which was applied to the Hangzhou Metro Line 1 project across the Qiantang River. By the targeted control of 55 driving units, the earth pressure balance shield was adopted successfully for the project crossing the Qiantang River for the first time.