The utility model relates to a multi-layer casing-tube cutting bullet for an oil well in the shallow sea, comprising an inner cutting bullet and an outer cutting bullet. The utility model is characterized in that metal liners are added respectively in the energy-storing groove of the inner and the outer cutting bullets, and the cutting charging tail of the inner cutting bullet is added with an explosion suppression plate and a cutting charging device. The outer cutting bullet is composed of two semi-circular rings which are combined, and the waste oil well of the oil field in the shallow sea can be cut only one time into two casing tubes and one layer of cement or three casing tubes and two layers of cement. The cutting surface can be regular, the mark can not be retained by more than the mud line of the sea floor, and the success ratio can be 100%.