Liquid-storage-type emptying-preventing oil well pump

A liquid-storage-type emptying-preventing oil well pump comprises a plunger assembly, a liquid storage cavity, a pump barrel, a fixed valve assembly and kerfs. The liquid-storage-type emptying-preventing oil well pump is characterized in that the outer periphery of the middle of the pump barrel is provided with the annular liquid storage cavity, the rapid liquid-discharging kerfs are axially and evenly formed in the inner periphery of the position, sleeved with the liquid storage cavity, of the pump barrel, and the length of each kerf is smaller than that of the plunger assembly. After the oil well pump is in an emptying state, when a plunger arrives below the liquid storage cavity every stroke, the liquid storage cavity is filled with liquid under oil pipe liquid column pressure. When the plunger arrives above the liquid storage cavity every stroke, the liquid contained in the liquid storage cavity flows into the pump barrel under the action of gravity. After accumulation in a plurality of strokes, clearance space will be filled with the liquid. When a piston descends, because the liquid cannot be compressed, pressure in the pump barrel is suddenly increased, space for containing gas does not exist in the pump barrel any more, the gas is forced to be exhausted out of the pump barrel through a movable valve, and a gas lock is opened. The liquid-storage-type emptying-preventing oil well pump is simple and reliable in structure, low in cost and suitable for oil wells where pump emptying occurs easily due to insufficient liquid supply.