Abstract: Taking the Hangfa Factory station-Renmin Road station of shield tunnel of Hangzhou metro line 2 as the background, an analysis on the cutter wearing during shield construction in the upper soft and lower hard mixed stratum is conducted, a series of abnormities caused by severe cutter wearing are revealed, including abnormal driving parameters, abnormal shield mucking, severe ground surface settlement and so on; in light of the unexpected severe cutter wearing, a treatment method combining foundation reinforcement and cutter replacement in atmospheric pressure and the countermeasures of soil conditioning, equipment configuration optimization and parameter control are proposed. The results show that the cutter wearing can be controlled within allowed range by optimizing the countermeasures of shield construction in mixed stratum.