The relative viscosity and intrinsic viscosity of collagen, gelatin and hydrolyzed collagen were determined by Ubbelohde’s viscosity method. The free amino group molar concentration of samples was determined by trinitrobenzene sulfonic acid (TNBS) method. The moisture absorption of samples was measured under different relative humidity environments. The method of fluorescent labeling samples to observe their distribution and penetration on the surface of rat skin, and keratinocyte culture experiments to evaluate the biological activities of the three samples, and to study the differences in physical and chemical properties and skin care functions of the three samples. The results show that the relative viscosity of collagen is about 5 times that of gelatin and hydrolyzed collagen, and its intrinsic viscosity is also significantly greater than that of gelatin and hydrolyzed collagen; collagen has the smallest molar concentration of free amino groups, followed by gelatin, and hydrolyzed collagen is the largest; collagen Hygroscopicity is better than gelatin and hydrolyzed collagen; collagen, gelatin and hydrolyzed collagen can penetrate into the hair follicles, but only collagen is still evenly distributed on the skin surface, showing its excellent moisturizing function; only collagen can significantly promote cell Growth and reproduction, and the growth of keratinocytes cultured on gelatin and hydrolyzed collagen is similar to the reference sample. Therefore, collagen has better moisture absorption, moisturizing properties and anti-aging effects than gelatin and hydrolyzed collagen.