It is very important to reduce the construction risk of shield disc cutter replacement. The shield disc cutter replacing places of seacrossing section of Xiamen Rail Transit Line No. 2 are predicted based on theoretical prediction model and testing prediction model under different kinds of rocks. The shield disc cutter replacing places and technologies are proposed by analyzing the feasibility of cutter replacing technologies. 1) The cutting cutter is used in silt soil; 〖JP2〗the cutter is replaced close to connecting gallery No.1 under atmospheric pressure. 2) The disc cutter is used in fullyweathered soil with low pressure; the cutters should be replaced by 4 times under hyperbaric pressure (1 times at intermediate ventilation shaft No. 1 and 3 times under sea). 3) The disc cutter is used in fullyweathered soil with high pressure; the cutters should be replaced by 4 times under saturated air hyperbaric pressure. 4) The disc cutter is used in moderatelyslightly weathered soil; the cutters should be replaced by 3 times by using pressure reduction method.