The invention discloses a piston type flow regulating valve. The piston type flow regulating valve comprises a valve body, a valve cavity is formed in the valve body, an inlet pipe is arranged at theleft end of the valve body, an outlet pipe is arranged at the right end of the valve body, a valve block is fixedly arranged in the outlet pipe, a valve hole is formed in the valve block, a convex block is arranged on the inner side wall of the valve cavity in an extending mode, a valve groove is formed in the convex block, a convex shaft is arranged in the valve groove, a shaft hole is formed inthe convex shaft, a valve rod is arranged in the shaft hole, a spiral groove is formed in the outer side of the valve rod, a first convex column is arranged on the side wall of the shaft hole, a valveclack is arranged at the right end of the valve rod, a first valve cylinder is arranged in the valve cavity, a second valve cylinder is connected in the first valve cylinder in a rotating mode, a blind plate is arranged at the left end of a second valve cylinder, the valve rod is provided with a rotary drum, the outer side of the rotary drum is sleeved with a sleeve, a convex ring is arranged onthe left side of the blind plate in an extending mode, a driving assembly is arranged on the valve body, and a transmission assembly is arranged among the rotary drum, the sleeve and the convex ring.The piston type flow regulating valve has the advantages of being reliable in sealing and compact in size.