The invention discloses a preparation apparatus and a preparation method for a gel polymer lithium ion battery. The preparation apparatus comprises two first containers, two second containers, two groups of first pulley groups, two groups of second pulley groups, an extrusion roller and a winding apparatus, wherein the two first containers are filled with an electrolyte; the two second containers are filled with a gel electrolyte precursor solution; the two groups of first pulley groups are wound with a positive plate and a negative plate respectively; when the first pulley groups turn, the first pulley groups drive the positive plates and the negative plates to be wetted in the electrolyte; the two groups of second pulley groups are wound with diaphragms respectively; when the second pulley groups turn, the second pulley groups drive the diaphragms to be wetted in the gel electrolyte precursor solution; the extrusion roller enables the positive plate, the diaphragm, the negative plate and the diaphragm which are wetted to be extruded together in sequence; and the winding apparatus is used for winding the extrusion material so as to assemble the battery. The preparation apparatus and the preparation method provided by the invention are used for solving the technical problem of low reliability of the battery caused by the reason that the positive and negative plates cannot be well wetted by the electrolyte and by a plurality of shortcomings existing in the thermal polymerization process; and in addition, a technical effect of improving the reliability of the battery is realized.