The invention aims to provide a large-dive-depth Kinston valve with small valve opening force. The large-dive-depth Kinston valve comprises a hand wheel, a valve rod, a valve rod power block, a bearing box, a valve body, a valve head and a reinforcement rod mechanism, wherein the hand wheel is connected with the valve rod power block through a spline, the upper portion of the valve rod is sleeved with the valve rod power block, threads on the upper portion of the valve rod are matched with the valve rod power block, the bearing box is arranged outside the valve rod power block, an upper angle thrust bearing and a lower angle thrust bearing are arranged in the bearing box, the valve rod power block is provided with a protrusion, the upper angle thrust bearing is located above the protrusion, the lower angle thrust bearing is located below the protrusion, the bearing box is connected with the valve body, the lower portion of the valve rod is located in the valve body, a valve head cover is arranged in the valve head, the head of the valve rod is located in a cavity formed by the valve head cover and the valve head, and a moving space is formed between the head of the valve rod and the valve head when the head of the valve rod is attached to the valve head cover. According to the large-dive-depth Kinston valve, a two-level reinforcement mechanism is adopted, and the valve opening force is greatly reduced. The seal surface of an end mouth of the valve is protected, and reliability of the valve is enhanced.