The utility model relates to an oil inlet/outlet pipe detaching-free device of a pressure-type oil filter, which comprises an upper straight pipeline and a lower straight pipeline. The upper straight pipeline and the lower straight pipeline are arranged in a spacing manner. The device is characterized in that: a right inclined pipeline which is communicated with the upper straight pipeline and the lower straight pipeline is arranged between the left segment of the upper straight pipeline and the right segment of the lower straight pipeline; a left inclined pipeline which is communicated with the upper straight pipeline and the lower straight pipeline is arranged between the left segment of the lower straight pipeline and the right segment of the upper straight pipeline; a right inclined pipeline switch used for opening or closing the right inclined pipeline is arranged on the right inclined pipeline, and a left inclined pipeline switch used for opening or closing the left inclined pipeline is arranged on the left inclined pipeline. The oil inlet/outlet pipe detaching-free device not only solves the disadvantages that the frequent on-site replacing of oil inlet/outlet pipelines is time-consuming and can easily pollute the ground, but also solves the problem that bubbles remain in oil pipes when oil is filled in a transformer.