Climbing film evaporator is composed according to the principle of siphon pump liquid into the heating tube, heating tube consists of a heat exchange tube, raw material preheating at or near boiling point, is composed of a heating chamber bottom is introduced into the tube, heat after boiling rapid vaporization, the heating tube is formed in the center of the steam cylinder, high speed rising two steam with animal feed along the wall surface film flow, at the same time at the top of the heating chamber of evaporation, can achieve a required density, vapor liquid on top of the separation chamber separated by a separation chamber, the liquid discharged at the bottom.