Objective To explore the application value of Carbon Nanoparticles followed by microscale Methylthioninum Chloride in sentinel lymph node biopsy for breast cancer.Methods Two hundred and eight breast cancer patients were selected in the First Affiliated Hospital of Zhengzhou University during recent two years who performed sentinel lymph node biopsy.They were randomly divided into five groups according to different lymphatic tracer injected:Sequential group (A group,128 patients),Carbon Nanoparticles group (B group,44 patients) and Methylthioninum Chloride group (C group,36 patients).According to different Methylthioninum Chloride doses,sequential groups were randomly divided into low dose group (A1 group,48 patients),middle dose group (A2 group,42 patients),high dose group (A3 group,38 patients),If sentinel lymph nodes were negative no longer performed axillary lymph nodes dissection.Receive the five groups statistics of detection rate,the condition of lymphatic tracer,the incidence of local skin irritation and so on.Results (1) The detection rate of A,B and C three groups had no obvious difference.The incidence of lymphatic tracer dyed not ideal in B group was higher than A and B two groups,the incidence of local skin stimulation in C group was higher than A and B two groups.(2) A1,A2,A3,three groups had no difference of the detection rate and lymphatic tracer,but the incidence of local skin stimulation in A3 group is higher than A1,A2 two groups.3.5 groups of SLN detection rate had no relationship with patients' age,BMI,tumor size,tumor location,tumor molecular classification factors (P ＞ 0.05).Conclusions Carbon Nanoparticles followed by microscale Methyhhioninum Chloride detection rate was similar with two separate application,but can reduce the lymphatic vessels not developing situation when used Carbon Nanoparticles alone and reduce the local irritation caused by large dose of Methylthioninum Chloride,so it can be a good choice of SLNB in clinical.