The utility model discloses an automatic air bleeder of plunger pump belongs to the oil and natural gas field. The device includes: the casing that has the tee bend structure, pressure cap with the last end connection of casing, with the regulation pole of pressing cap swing joint, the lower tip of just adjusting the pole stretches into in the inner chamber of casing, spring with the lower end connection that adjusts the pole, floater with the lower end connection of spring, carry out the blast pipe of being connected with pressing the cap, and the lower tip of blast pipe stretches into in the inner chamber of casing, the otic placode of being connected with the lower terminal surface of pressing the cap, carry out the connecting rod be connected with the lower tip of otic placode, and the left end portion of connecting rod is connected with the floater, carry out the shutoff dish be connected with the upper end surface of connecting rod, and the position of tip is corresponding under shutoff dish and the blast pipe, the diameter of shutoff dish is more than or equal to the internal diameter of blast pipe. The utility model provides an automatic air bleeder of plunger pump has reduced staff intensity of labour and cost of maintenance.