The invention relates to a method for determining colorectal cancer suffering possibility of individuals in vitro in a peripheral blood sample. The method comprises the following steps: comparing the amount of a nucleic acid expression product of the gene of an individual to be detected, the mount of a nucleic acid expression product of the same gene of a CRC patient group obtained from positive control and the amount of nucleic acid expression product of the same gene of a CNC individual group from negative control. The invention further relates to a kit which comprises a specific binding gametophyte of the expression product.