The invention discloses a blanking method and system for an automobile plate. The blanking method comprises the following steps of: arranging automobile plate sheets, determining the shape and size of an assembly material according to the multiple lengths of the sheets, and cutting into an assembly material; designing a lining plate die according to waste to be cut from the assembly material, andhollowing the lining plate die correspondingly to the waste to form a blanking hole, wherein the size of the blanking hole is larger than the blanking size of practically-cut waste; placing the assembly material on the lining plate die; performing laser cutting on the assembly material according to the shape of the automobile plate sheet and making the cut waste fall onto a lower waste conveying belt through the blanking hole of the lining plate die; and stacking the cut sheets. Due to the adoption of the method and the system, waste can be treated effectively, and the blanking efficiency is increased.