Fan with variable-diameter nozzle

The invention relates to the technical field of fans, and discloses a fan with a variable-diameter nozzle. The fan with the variable-diameter nozzle comprises a base, a first electric push rod is fixedly connected to the upper surface of the base, a protection box is fixedly connected to the output end of the first electric push rod, a mounting base is fixedly connected to the interior of the protection box, and a fan is connected to the interior of the mounting base in an embedded mode; the input end of the fan is fixedly connected with an air inlet pipe, the output end of the fan is fixedly connected with an exhaust pipe, the end, away from the fan, of the exhaust pipe is in threaded connection with a jet head, the side surface of the exhaust pipe is fixedly connected with a first flange ring, and the lower surface of the first flange ring is fixedly connected with a connecting cylinder; the end, away from the first flange ring, of the connecting cylinder is fixedly connected with a second flange ring, and