Objective To study the human telomerase reverse transcriptase (hTERT) and spleen tyrosine kinase (SYK) activity expression and molecular margin in the tumor center and peripheral tissues of patients with colorectal cancer, and to explore the security of tumor surgical margins. Methods The expressions of hTERT and SYK were examined by SABC and Supervisan immunohistochemistry in 20 specimens of colorectal cancer and tissues 1 cm, 2 cm, 3 cm, 4 cm and 5 cm, away from proximal and distal margin of the tumor respectively. Results The positive expression rate of hTERT in colorectal cancer was 80.00 %, the rate in tissues 3 cm, 4 cm and 5 cm away from the tumor margin was 0. The positive expression rate of hTERT in tissues from the cancer center to 3 cm away from the tumor margin was gradually diminishing (P<0.01). The positive expression rate of SYK in colorectal cancer was 10.00 %, the positive expression rate of SYK in tissues from the cancer center to 3 cm away from the tumor margin was gradually increased (P<0.05). Conclusion There is molecular margin around colorectal cancer tissues. Considering hTERT and SYK expressions, 3 cm can be defined as the safe molecular margin for the radical operation of colorectal cancer.