The utility model relates to lifting appliances, in particular to a lifting jacket for a post-tensioned precast box girder, which solves the problem that transferring by a jack is time-consuming, labor-consuming and higher in energy consumption. The lifting jacket for the post-tensioned precast box girder comprises a rotary shaft penetrating through a lifting hole, a limiting steel plate is fixed on the rotary shaft, a cantilever rail which is perpendicular to the rotary shaft and positioned above the limiting steel plate is sleeved on the rotary shaft, a pulley sliding on the cantilever rail is arranged on the same, a chain hoist is arranged on the pulley, a baffle plate is disposed at the outer end of the cantilever rail, and a rope tightener is arranged between the upper end of the rotary shaft and the outer end of the cantilever rail through a steel wire rope. The lifting jacket is reasonable and ingenious in structural design, the lifting jack is disposed by the aid of the lifting hole, and thereby quick and laborsaving sliding of the jack is realized. The lifting jacket for a post-tensioned precast box girder has the advantages of simple structure, convenience in operation and lower cost.