A simple oil vacuumizing device for a distribution network transformer comprises a tank, wherein the tank is provided with an oil inlet and an oil outlet. The upper portion inside the tank is provided with an inverted bowl-shaped diffuser, the air inlet is arranged at the bottom of the tank and is led to the tank through an oil inlet pipe, the tail end of the oil inlet pipe is located at the lower end of the bowl-shaped diffuser, and the top end of the tank is provided with a vacuumizing port. The simple oil oil vacuumizing device is rational in design, convenient to arrange and flexible to connect. The oil vacuumizing device can be connected and matched with an oil pump, a heater, an adsorption tank, a vacuum switch and a temperature regulator and is connected with an oil valve on the upper portion of a distribution transformer to perform treatment on transformer oil. The simple oil oil vacuumizing device is simple in structure, appropriate in weight and convenient to carry and can be randomly moved on the site. When the simple oil oil vacuumizing device is used, oil flows through the oil inlet and impacts the bowl bottom of the bowl-shaped diffuser through the tail end of the oil inlet pipe; and oil flow impact is dispersed to be favorable for separating out gas in the oil. The pressure resistance of transformer oil can be improved to over 40 kV, the volume resistivity is improved by one order of magnitude, and transformer insulation resistance is greatly improved.