The invention discloses a pressurization control loop and method of a piling machinery power head. The pressurization control loop is a pressurization logic control loop designed through electric hydraulic combined control. The control loop is simple and convenient for a pressurizing winch to coil/uncoil a rope, and convenience in loading and unloading is realized. By the control method, the pressure of pressure oil in the loop is controlled by an overflow valve and a check valve, so that when a main winch hoists, the pressurizing winch can automatically uncoil the rope along the main winch; when the main winch lowers, the speed of the pressurizing winch to coil the rope is perfectly matched with the speed of the pressurizing winch to uncoil the rope; when the pressurizing winch pressurizes, the pressure is controlled by the overflow valve, so that the condition that the pressure of the power head is controllable is realized.