The invention discloses a street tree pruning machine which solves the problems that for an existing street tree pruning machine, the labor intensity is high, and the potential safety hazard is high. According to the street tree pruning machine, a rotary table (13) is arranged on a vehicle chassis (14), a power assembly (1), a driving cab (2) and a bending arm (3) are installed on the rotary table (13), and the lower end of a big arm (4) of the bending arm (3) is movably connected with the rotary table (13) through a hinge device (12) and a lifting cylinder (10); the bending arm (3) comprises the big arm (4), a small arm (6) and a grasping cutting device (9), the upper end of the big arm (4) is movably connected with one end of the small arm (6) through a hinge pin and a telescopic cylinder (5), the other end of the small arm (6) is connected with the grasping cutting device (9) through a link mechanism (7) and a connecting part (8), the telescopic cylinder (5) is arranged on the small arm (6), one end of the telescopic cylinder (5) is connected with the small arm (6), and the other end of the telescopic cylinder (5) is rotatably connected with the connecting part (8) and the other end of the small arm (6) through the middle of the link mechanism (7).