The utility model discloses chemical equipment and particularly relates to a falling film evaporation device of a liquid material. The device comprises an upper cover, a lower cover and a pipe body connected by flanges to form a barrel, wherein a feed inlet is formed in the upper end of the upper cover and a distributing disc is connected to the lower part of the upper cover; a steam chamber is arranged on one side of the pipe body located below the distributing disc, the steam chamber is connected with a steam inlet, an exhaust opening is formed in one side on the upper part of the lower cover while a suction opening is formed in the other side on the upper part of the lower cover, and a discharge opening is formed in the lower part of the lower cover. A plurality of orifices are formed in the distributing disc, the lower end of each orifice is connected with a distributing head and the outer wall of the distributing head is sleeved with a hollow tube. The distributing head consists of the upper cover, an S-shaped guide slot, a second-level distributing plate and a third-level distributing plate, so that the to-be-concentrated liquid entering the distributing head is subjected to three-level guiding through the S-shaped guide slot, the second-level distributing plate and the third-level distributing plate to form a uniform membrane which moves downward along the inner wall of the tube to the maximum extent, so that the heat efficiency and the production efficiency are greatly improved. Heating steam entering the falling film evaporation device is split to move downward through a flow split baffle in the barrel to carry out full heat exchange, so that the heat utilization ratio is increased.