Objective To evaluate the feasibility of sentinel lymph node (SLN) mapping after 99Tcm sulfur colloid (99Tcm-sc) and carbon nanoparticles injection in patients with colon cancer. Methods Forty patients with colon cancer underwent complete mesocolic excision between August 2015 and July 2016 at Qingdao Central Hospital were considered for prospective inclusion. Before resection, SLN mapping was performed with injection of 99Tcm-sc and carbon nanopar-ticles, then all dissected lymph nodes were detected by pathological examination. Results A total of 660 cases of lymph nodes were found in the 40 patients (average of 16.5 cases per patient). Of them, 88 nodes (average of 2.2 cases per patient) were identified as SLN in 36 of 40 patients, with a successful detection rate of 90.0% (36/40). The diagnostic accuracy, sensitivity, and false-negative rate were 87.5% (35/40), 96.2% (25/26), and 3.8% (1/26) respectively. Conclusion 99Tcm-sc and carbon nanoparticles suspension injection for mapping SLN is a feasiblely diagnostic method for predicting local lymph node metastasis in the patient with colon cancer.