The invention relates to an automatic pin cutting mechanism of a Y capacitor. The automatic foot cutting mechanism of the Y capacitor comprises a support plate, wherein a vibration material conveying disc and a discharging groove which are mutually matched are arranged at the left part of the support plate; a conveying belt, a conveying device and a pin cutting device are arranged at the right part of the support plate; the conveying belt and the conveying device are mutually matched; the pin cutting device is matched with the conveying belt; an insertion sleeve matched with a capacitor pin is arranged on the conveying belt; a transfer conveying device matched with a discharging opening of the discharging groove and the conveying belt is arranged at the front part of the support plate, and comprises a left and right moving device; a front and back pushing device is arranged on the left and right moving device; a first clamping air cylinder is arranged on the front and back pushing device and is connected with a first clamping block matched with the Y capacitor. The Y capacitor arranged at the discharging opening is clamped through the transfer conveying device and is transferred and conveyed onto the conveying belt matched with the Y capacitor; then, the conveying belt is driven to move through the conveying device; the pin of the Y capacitor is trimmed through the pin cutting device; the automation operation is realized; the pin cutting efficiency is greatly improved; the labor work is reduced.