The original cutters of the shield machine is easily worn and eccentrically worn when drilling through the sandy gravel, mudstone and fine sand strata layers where Chengdu Metro Line 1 is located. After a comparison of the relationship between the cutters and the strata, such measures as a replacement of disc cutter by gear cutter and thickening the cutter ring of the common disc cutters are put forward, which have gained good implementation effect.