The invention provides a separating type prefabricated bay window mold which comprises a mold table. A convex table is arranged on the mold table. First mold plates located on the front side and the back side of the convex table are arranged on the mold table. Second mold plates and third mold plates located on the left side and the right side of the convex table are arranged on the mold table. The second mold plates are located on the upper portions of the third mold plates. The second mold plates are arranged between the first mold plates on the front side and the back side. The third mold plates are arranged between the first mold plates and the convex table. Cross beams is arranged between the first mold plates on the front side and the back side and provided with movable embedded parts, and scales are marked on the cross beams. The separating type prefabricated bay window mold has the advantages that the mold is adopted for prefabricating a bay window, industrialized manufacturingis achieved, field links are reduced, the construction efficiency is improved, the locating precision of the embedded parts and reserved holes is improved, and quality is guaranteed.