The invention belongs to a bridge side position pier-crossing girder elevating bracket device and a simple and quick construction method thereof. The method is as follows: a base pier is fixed on a shore at one side of a river, and a bottom bracket is fixed on the base pier; a roof pier is located on a capping girder or a box girder on the bridge corresponding to one side of the base pier, a lowerend of a top bracket is fixed on the roof pier; a crane transverse suspension girder is arranged at an upper space formed by the upper end of the bottom bracket of the shore and the top bracket on the capping girder or the box girder on the bridge, a crane on the crane transverse suspension girder is used for accomplishing the hoisting and mounting of the box girder to the bridge surface from theshore. The device comprises a bracket unit, the roof pier, the base pier, the crane transverse suspension girder, connecting bolts, nuts, the crane, a hoist and a hoisting steel wire rope. The methodand device disclosed by the invention are simple and feasible, fast in construction speed, time-saving and labor-saving, low in construction cost, good in construction quality, good in security and good in use effect.