Sand control oil -well pump and plunger thereof

The utility model discloses a sand control oil -well pump and plunger thereof. The ascending extension cylinder of outer peripheral face of the plunger body of plunger is in within the outer peripheral face of delivery valve. Like this at the oil recovery in -process, the outer peripheral face of delivery valve will be in the top of pump barrel all the time, and the part that the periphery of delivery valve is exposed from the periphery of plunger body will be sheltered from in the formation of the top in the clearance between pump barrel and the plunger body, with the sand grain that blocks that pump barrel top deposit gets off, avoid these sand grains to fall into the clearance between pump barrel and the plunger body, especially, when the plunger arrives down stroke limit position down, the part that the delivery valve exposes from the periphery of plunger body can be sealed up the port of fitting with a contraceptive ring in the clearance between pump barrel and the plunger body, consequently the utility model discloses well plunger can effectually prevent that the sand grain that the oil pipe deposit is got off on the pump from falling into the pump barrel, avoids appearing sanding and sand card phenomenon between plunger and the pump barrel.