Disclosed is a device and method for preparing composite ice glaze, relating to the field of freshness of aquatic products. The device includes a frame portion, a mother liquid preparation portion, an ice glaze preparation portion, an ice glaze post-processing portion and a controller system; the frame portion includes a shell, a base, and a thermal insulation baffles; the mother liquid preparation portion includes a main water inlet pipe, a water storage tank, mother liquid tanks; the ice glaze preparation portion includes a homogenizing tank, a homogenizing tank inlet pipe, a waste cylinder inlet pipe; the ice glaze post-processing portion includes a reception cylinder, and a waste cylinder. The device provided by the invention is simple to use, and the prepared concentration is accurate and effective, so that the compounding process can be simplified and the compounding efficiency is effectively improved.