The invention belongs to a collagen detection method and particularly relates to a method for detecting collagen fiber content in collagen, comprising the steps of (1) folding gauze, drying, and metering; (2) drying collagen, and calculating its water content; (3) preparing a collagen solution; (4) adjusting pH; (5) suck-filtering with gauze; (6) drying, and metering to obtain mass of a material obtained by suction filtering; (7) calculating the content of collagen fiber. The method that detects the collagen fiber content in collagen has high detection efficiency and good accuracy, allows the quality of a process of pretreating raw skin to be evaluated in order to adjust the pretreatment process of the raw skin to obtain the optimal treatment process suitable for different types of raw skin, enterprise production cost is saved, and production efficiency is improved.