The present invention relates to an arm soft fixing splint dressing applying device. The arm soft fixing splint dressing applying device comprises a bottom plate, a mounting frame, a clamping conveying device, a material applying device and a film coating device, an upper end of the bottom plate is provided with the mounting frame, the mounting frame is internally provided with the clamping conveying device, the material applying device is arranged at a left side of the mounting frame, the film coating device is arranged at a right side of an upper end of the bottom plate, and the film coatingdevice is located above a left side of the mounting frame. The arm soft fixing splint dressing applying device can solve problems that during use of existing soft fixing splints, use effects are generally poor and doctors need to apply dressing, leading to long consumption time and affecting work efficiency, besides, the existing soft fixing splints need to be used with bandages and cannot directly adhere to patient's arms, etc., can realize automatic dressing applying and film coating of the soft fixing splints, and has advantages of being good in use effects, shortening time for the doctorsto apply the medical dressing, being capable of directly adhering to the patient's arms, good in use effects, etc.