Objective To investigate the diagnosis and surgical therapy of multiple primary colorectal carcinoma. Methods From 1998 to 2007, 47 patients with synchronous multiple primary colorectal carcinoma and 20 cases with metachronous carcinoma were treated in our hospital. Results In these 67 cases of multiple primary colorectal carcinoma, synchronous carcinoma (SC) accounted for 70% (47 cases) including 37 rectal cancer with a total of 95 larger bowel cancer lesions. There were 6 cases with Dukes A stage, 22 cases with Dukes B stage, 15 cases with Dukes C stage and 4 cases with Dukes D stage. In this whole group there were 20 cases with lymph node metastasis, 21 cases with adenoma and multiple polyps in SC. Three cases received total coloectomy, 10 cases did subtotal coloectomy, 34 cases were treated by radical resection and intestine segment resection. In 20 metachronous carcinoma cases, there were 31 colon cancer(70%) with a total of 44 intestinal cancer lesions. Altogether, there were 17 cases with two tumors, 2 cases with three tumors, one case with four tumors. The duration between the first and the last carcinoma was from 7 months to 19 years, including less than two years in 7 cases, from two to five years in 5 cases, and more than five years in 8 cases. In all 20 MC cases the first (primary) carcinoma received radical resection, while radical resection was performed for the secondary carcinoma in 14 cases and for the third carcinoma in 2 cases. In the SC and the primary carcinoma of MC patients who received radical resection, the 5-year survival rates were 74% and 78% respectively. Conclusion In cases of colonic carcinoma we shouldn't be satisfied with the diagnosis of single colon tumor before a thorough screening of the whole colon was made. In radical resection surgery for SC or MC cases an attempt to preserve enough residual intestinal tract should be made in order to improve the life quality of post-operative patients.