The utility model belongs to the field of power application, and relates to a flow control device for a transformer oil filter. The device comprises a positive displacement oil pump (1), a frequency converter (3), and an oil inlet (7). The positive displacement oil pump (1) driven by an AC asynchronous motor (2) is disposed behind the oil outlet (7). The AC asynchronous motor (2) is in control connection with the PLC controller through the frequency converter (3). A flow sensor (5) is disposed in front of an oil outlet (6). The oil outlet (6) of the system is provided with the flow sensor (5), thereby facilitating the real-time detection of oil pump capacity. The oil flow can be within the range from 7 L/min to 80 L/min, and the error is +/- 0.2 L/min. The device achieves the real-time calculation, adjustment and control according to an oil pump capacity detection signal, and enables to the results to be fed back to the frequency converter 3, thereby controlling the oil pump capacity of the device.