The invention relates to a liquamatic type ship lift downstream quick butt joint method. Ship compartment clamping in the downstream butt joint process is replaced with an abnormal-shaped rail and guide fit, brake open gate butt joint avoids ship lift gate release condition judgment and the counterweight submerging water depth adjustment procedure, and the ship lift running efficiency is improved. After ship compartment replacement clamping, the maneuverability of a ship lift is increased, quick butt joint release can be achieved under the condition of too large downstream water level variation amplitude, and the conditions that a ship compartment is submerged with water and the running water depth in the ship compartment is insufficient are avoided.