The invention relates to a preparing and collecting device and a preparing and collecting method for an oil sample of an analogue transformer. By manually matching a main oil tank, an adjusting oil tank and an auxiliary oil tank, transformer oil of multiple typical transformers in a failure state can be accurately produced; various characteristic gas components and contents in oil can be accurately controlled and can be preserved at normal temperature at a constant value. The device provides multiple parallel stations, can completely simulate actual collecting process of the oil sample of the transformer, and can be safely and conveniently used for works such as skill training, examination, technological competition and the like of professional practitioners for oil chemical examination, electrical test/examination and the like; the device is low in application cost, safe in operation, high in integrating degree with field operation, convenient and quick; transformer oil adopts a mode of reutilization and purifying, and recycling, so economy and environmental protection are realized.