The production process of the ultra-thin casing membrane is to mix the raw material nylon and masterbatch uniformly, enter the extruder heating zone to melt the nylon material and the masterbatch, and then squeeze the barrel-shaped film through an extruder to cool, drain, and drain. After that, it enters the secondary heating and is squeezed and rolled into a nylon strip. The nylon strip is stretched in the transverse direction by the internal air expansion. The stretching machine is stretched 2.5 times in the longitudinal direction, curled into a disk shape by the high temperature setting, and finally made into an ultra-thin casing. The invention is suitable for filling various types of sausage products, and can be used for smoking and hot processing of the filled products without losing the inherent quality and weight, and the shelf life is long.