Background: As a common complication of diabetes, the incidence of diabetic peripheral neuropathy (DPN) is 60-70% worldwide. DPN is a major risk factor for diabetic foot, which may lead to foot ulceration and even amputation. The treatment of DPN remains challenging. Our preliminary study demonstrated that the external application of Tangbi Waixi (TW) decoction to the lower extremities relieved clinical symptoms and improved nerve conduction velocity in DPN patients. The aim of this study was to verify the efficacy of TW among DPN patients and evaluate the herb mixture's safety using rigorous methodological designs. Methods/design: This study is a multicenter, double-blind, randomized controlled trial. A total of 640 DPN patients will be recruited and randomized to receive a foot bath with either the TW decoction or control drug. Participants will be assessed at baseline and 12 and 24 weeks after treatment. The primary outcome was the change of the Toronto Clinical Scoring System (TCSS). Secondary outcomes were nerve conduction velocity, blood glucose, blood lipids, serum inflammatory cytokines, and the European Quality of Life Five-Dimension Scale (EQ-5D) and TCM symptom scores. Discussion: This multicenter, prospective, randomized clinical trial will provide valuable data regarding the efficacy and safety of foot bath treatment with TW decoction. Positive results would provide a novel treatment regimen for DPN patients.