Background: Cancer-related fatigue (CRF) is the most common symptom in patients with advanced non-small cell lung cancer (NSCLC) undergoing treatment with chemotherapy. However, evidence upon which to base management strategies is scarce. Traditional Chinese Medicine (TCM) has been shown to be beneficial to patients with CRF. Chinese herbal injections should be administered under an evidence-based approach. This trial aims to assess the efficacy and safety of the addition of the Shenmai injection (SMI) to conventional therapy for CRF in NSCLC patients undergoing chemotherapy. Methods/design: The study is a two-group, prospective, randomized controlled trial (RCT) designed to evaluate the efficacy and safety of SMI for CRF NSCLC patients undergoing chemotherapy. Eligible participants will be randomized to either a treatment group receiving a 5-day Shenmai injection regimen plus conventional therapy or a control group receiving only conventional therapy. The primary outcome is fatigue, assessed using severity scores from the Functional Assessment for Chronic Illness Therapy-Fatigue (FACIT-F) measurement system. Secondary outcomes include symptom distress scores, depression, sleep disorders, quality of life, and levels of immunologic indicators. Assessments will be carried out at baseline and on day 5 (the end of the intervention). Discussion: This study can provide evidence to support clinical decision-making in the management of CRF in NSCLC patients undergoing chemotherapy in a way that can be scaled up and used throughout China.