The invention discloses an angle-adjustable conical branches and leaves trimming device, which comprises a top base, a connector, a middle bracket, a counter weight device, a trimming arm, a track slot, a screw, a motor, an angle adjusting lever, a nut, a driving gear, a frustum gear, a rotary shaft, a trimming cutter; the connector is fixedly connected to the top part of the top base, and the middle bracket is rotationally connected to the bottom part of the top base; the trimming arm is hinged at one end of the middle bracket, and the counter weight device is fixedly connected to the other end of the fixing bracket. The motor drives the screw so that the nut is moved on the screw; meanwhile, the screw is rotated, and the trimming cutter is also driven to rotate through the driving gear and the frustum gear, thereby realizing the trimming at one side of a tree; the tree can be trimmed to be a conical form through rotating the middle bracket for many times. The method is simple and high-efficient, the work load of technicians is lightened; shapes of trimmed trees are uniform, the coordination and beauty of a garden landscape are guaranteed.