The invention discloses an oil-inlet and oil-outlet interface conversion apparatus for an oil filter. The oil-inlet and oil-outlet interface conversion apparatus comprises a first tee-joint conversion switch, a second tee joint conversion switch and multiple pipelines, wherein the multiple pipelines comprise a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a fifth pipeline and a sixth pipeline; one end of the first pipeline is connected with the third pipeline while the other end of the first pipeline is connected with a third pipeline opening of the second tee joint conversion switch; and one end of the second pipeline is connected with the fourth pipeline while the other end of the second pipeline is connected with a third pipeline opening of the first tee joint conversion switch. The oil-inlet and oil-outlet interface conversion apparatus is simple in structural principle, low in manufacturing cost, simple and convenient to operate, and capable of switching an oil inlet pipe and an oil outlet pipe of the oil filter without detaching the oil inlet pipe and the oil outlet pipe, thereby improving the oil-discharging and oil-filling efficiency and quality of a main transformer.