The invention relates to a knifing separator for waste lead-acid battery recycling treatment and a separation method. A blade height adjustment device, a compaction cavity and a cutting feed mechanism are disposed on a pedestal in a straight line, a clamping limiting plate is vertically disposed on a side opposite to a battery inlet inside the compaction cavity to guide the battery; a battery clamping mechanism is disposed in the horizontal front perpendicular to the straight-line direction, and the battery clamping mechanism pushes the battery into the compaction cavity from the compaction cavity front side to realize compaction and positioning; and the push end of the cutting feed mechanism can push the battery to a knifing position linearly from the compaction cavity to perform covering and knifing. According to the invention, a battery inlet push mechanism and a positioning clamping device have a simple and convenient structure, and the push knifing mechanism and all separators are simple and feasible and can have optimized design in space. By one cutting push, the upper part and lower part of the battery can be separated, and the cutting efficiency is high.