The invention discloses a biomass full-film type wall boiler. Front-film type walls, two-side-film type walls and rear-arch-film type walls are communicated between a corresponding lower collection box and an upper boiler cylinder of a boiler body of the biomass full-film type wall boiler to form a hearth with a fire grate in an enclosing mode, and the lower collection boxes are communicated with the rear-film type walls and the two-side-film type walls to form a flue with the upper boiler cylinder and a lower boiler cylinder in an enclosing mode. The hearth is designed to be of a full-film type wall structure, the weight of the boiler is reduced, air impermeability of the hearth is increased, the heating area is enlarged, it is beneficial to lower the temperature of the hearth, and generation of nitrogen oxide is inhibited; on the basis of the mentioned structure, the film type wall structure is also adopted for the flue, the heating area is enlarged, it is beneficial to lower the temperature of smoke discharged by the flue, the air leakage rate is reduced, and heating efficiency of the boiler is improved.