Abstract： Objective To study the possible influence of laparoscopic surgery on tumor micrometastasis via detecting the expression of CK2OmRNA in patients with coloreetal cancer. Methods Forty-four cases of colorectal cancer were divided into two groups: the laparoscopic surgery group(25 cases) and open surgery group( 19 cases).Blood samples were obtained 24 hours before the operation, intra-operation after finishing anastomosis, and 48 hours after operation respectively. RT-PCR was applied to detect the expression of CK20mRNA before-, intra- and post-operation. Results In the laparoscopic surgery group, 25 cases were CK20mRNA positive, whereas 50 cases were negative. The before-, intra-, post-operation expression of CK20mRNA positive cases were 8, 9, 8, respectively.In the open surgery group, 22 cases were CK20mRNA positive, whereas 35 cases were negative. The before-,intra-, post-operation expression of CK20mRNA positive cases were 9, 6, 7, respectively. Conclusion There was no significant difference of the expression of CK20mRNA before- and post-operation between the two groups.Laparoscopic surgery for colorectal cancer had little influence on tumor micremetastasis.