The invention discloses a pressure-adjustable-type windshield wiper arm device and a control method and relates to the technical field of windshield wipers. According to the pressure-adjustable-type windshield wiper arm device and the control method, a tension spring and a servo motor with a telescopic arm rod are included; and one end of the tension spring is clamped in a mounting hole of a wiperarm wiper rod, and the other end of the tension spring is clamped in a mounting hole in the telescopic arm rod. Through the structure, it is ensured that in whole wiping-brushing movement of a windshield wiper, as for the pressure applied by the wiper arm, the abrasion degree of a windshield wiper piece is not increased, perfect attaching of the windshield wiper piece and a front windshield of acar can be further ensured, and safety of traveling in rainy days is improved by a large margin.