The invention belongs to the technical field of lithium battery production, and particularly relates to a lithium battery pole plate weighing instrument. The lithium battery pole plate weighing instrument comprises a bottom plate, a base, support rods, a weight box, a cone block, a weighing box, a detecting unit and a feeding unit. The base is fixedly connected to the middle portion of the bottomplate; the middle portions of the support rods are rotatably connected to the end of the base; the weight box is rotatably installed at one ends of the support rods; the cone block is rotatably connected to the other ends of the support rods, and the rotation point of the cone block is set over the center of gravity of the cone block; the weighing box is fixedly connected at the top of the cone block, and a rotating plate is rotatably installed at the end of the weighing box; the cone block is used for keeping the weighing box horizontal; the detecting unit is mounted on the bottom plate, andthe detecting unit is used for screening unqualified pole plates; and the feeding unit is arranged above the weighing box, and the feeding unit is used for transporting the pole plates. The feeding unit is arranged to transport the pole plates, the pole plates to be weighed are put into the weighing box, the weighing box sinks under the action of gravity, and when the weighing box sinks beyond theset value, the detecting unit works to screen out the unqualified pole plates.