The invention belongs to the field of bridge construction processes, is applied in the construction of a movable shuttering form for a cast-in-place box girder, and particularly relates to a construction process for the overhead back-up movement and dismantlement of a movable shuttering form after a cast-in-place box girder is completely constructed by the movable shuttering form. The process is characterized in that: a back guide girder, a main beam, a front guide girder, a bracket, a cart, an external mould plate, a mould plate beam, a middle beam and bracket tensioning fining twisted steel on both sides of the bride need to be removed; the cart transversely moves on the bracket to open the movable shuttering form, a winder is arranged on a concrete box girder, the external mould plate is removed by the winder and by the drawing and hoisting operation of a truck crane, the mould plate beam and the middle beam are removed from the top to the bottom in sequence, only the back guide girder, the main beam and the front guide girder remain, the main beam of the movable shuttering form is removed, and finally the last section of main beam and the front guide girder are moved. The process has the advantages of speeding up the construction, reducing construction equipment, guaranteeing the construction safety and lowering construction cost.