The utility model discloses a lifting type truss mechanical arm for spraying. The lifting type truss mechanical arm for spraying comprises a truss structure, a stand column and a winch, wherein the winch is used for lifting the truss structure, the truss structure is movably connected with the stand column, a plurality of spraying boxes are arranged on the lower surface of the truss structure and provided with a plurality of nozzles, the truss structure and the stand column are each provided with a double-pulley block, and a steel wire rope of the winch is sequentially wound around the double-pulley block on the stand column and the double-pulley block on the truss structure and fixed to the stand column. The truss structure is adopted for the mechanical arm, on-site space is saved when the mechanical arm retracts, and occupied space is small. For a complex unorganized dust discharge site, dust can be removed intelligently in a dry spraying mode, and a better effect is achieved. The mechanical arm can be connected with a PLC or other switch sensors for automatic control, can also be manually controlled, and can work in a multiple-working-point mode.