Preparation method of collagen casing not easy to peel

The invention discloses a preparation method of collagen casings not easy to peel, which comprises the following steps of: controlling each spraying ring to work according to the rotating speed change of a conveying roller sensed by a rotating speed sensor: when the rotating speed of the conveying roller is increased by a preset amplitude, opening a liquid supply valve; the spraying rings corresponding to the liquid supply valves start to spray the modified treatment liquid to the collagen casings; and when the rotating speed of the conveying roller is reduced by a preset amplitude, one liquid supply valve is closed, so that the spraying ring corresponding to the liquid supply valve stops spraying the modified treatment liquid to the collagen casing passing through the spraying ring. The collagen casing prepared by the method is not easy to peel, and is resistant to water boiling and high-temperature frying; in addition, modification treatment liquid can be sprayed to the collagen casing through a plurality o