The structure of the back-pull modular drill is that the center locking screw can ensure that the insert is firmly clamped in the tool socket, thereby ensuring the safety of the drill body and the insert during the machining process and improving the service life of the tool. The internal coolant reaches the cutting zone directly for extended tool life and efficient chip evacuation. This tool is suitable for the machining of soft materials such as stainless steel, and its accuracy is higher than that of self-locking drills.