The stability and nutritional integrity of emulsions are susceptible to various factors including thermal treatment, solid–liquid ratio, and sterilization. In this study, the physicochemical stability and immunomodulatory activities of an oil‐in‐water emulsion containing immune peptides (TUFSE) were assessed through particle size, zeta potential, related cytokines, and so on. When the temperature was 70°C and a solid–liquid ratio of 1:4, the emulsion revealed stability at high‐pressure homogenization, with the small particle size. The loss rates of vitamins were 8.57%–62.26% in 6 months at 25°C. After treatment with cyclophosphamide (CTX), lymphocyte proliferation activity in TUFSE‐H group increased (p < 0.05), and immune globulin levels were notably elevated (p < 0.05) in TUFSE groups compared to model group. It confirms the parameters of the emulsion, suggesting its ability to be prepared with minimal vitamin loss while simultaneously improving the disease status in CTX‐treated tumor‐bearing mice. It shows potential as an immune‐enhancing supplement with significant potential value.Practical ApplicationThis study validated the parameters of the oil‐in‐water emulsion and showed that it can be stably prepared with minor vitamin loss while simultaneously improving the disease status in CTX‐treated tumor‐bearing mice. TUFSE‐H group exhibited a notable increase in lymphocytes proliferation activity, whereas serum cytokines and immune globulin levels were elevated compared to MC group, indicating its potential as an immune‐enhancing supplement with substantial value.