The tubing head is installed on top of the casing head, and its function is to suspend the tubing inside the well and seal the annular space between the tubing and the reservoir casing. At present, the hanging method of top screw valve is commonly used, which means installing a top screw valve on the four-way of the casing, and the top screw valve has a conical channel with a large upper part and a small lower part inside. The oil pipe hanger is also a conical problem, with a sealing ring on it. Under the tension of the entire wellbore oil pipe weight, the oil pipe hanger firmly sits in the seat of the top screw valve. The function of the top wire is to prevent the oil pipe column from being pushed out during high internal pressure.