To investigate the regulatory effect of non-denatured type-I collagen (NDC-I) on the immune function inimmunocompromised rats, the immunocompromised model was established by i.p. injection of cyclophosphamide in animal experiments The thymus index, spleen index, white blood cell count and classification, IgA (IgA) level, IgG (IgG) level, IL-2 (interleukin-2) level, IL-4 (interleukin-4) level, IL-10 (interleukin-10) level, IFN-γ (interferon-gamma) level, TNF-α (tumor necrosis factor-α) level, activity of lactate dehydrogenase (LDH) in spleen and thymus, as well as histomorphol. changes of spleen and thymus, were examined The results showed compared with the model group, a 30-day NDC-I intervention led to significant increases in the thymus index (p<0.05) and white blood cell count (p<0.01) of the NDC-I treated group, causing significant increases (p<0.01) in their levels of serum IgA, IgG, IL-2, IL-4, IL-10, IFN-γ and TNF-α (as 43.32 μg/mL, 283.32 μg/mL, 1827.17 ng/L, 135.97 pg/mL, 113.87 ng/L, 2302.44 pg/mL and 469.91 ng/L, resp.), and the activity of LDH in spleen. In addition, the histopathol. damages of the spleen and thymus were reduced. The obtained results revealed that the NDC-I treatment showed a regulatory effect on the immune function of cyclophosphamide-induced immunocompromised rats. This research also provides a reference for the comprehensive development and full utilization of collagen and other related functional products.