The invention relates to the field of state monitoring and maintenance of transformers, in particular to a transformer with built-in transducers. The transformer comprises a transformer body and the built-in transducers, wherein the transformer body comprises an oil tank, an upper clamping piece, a lower clamping piece, a cushion block, an iron core and a winding; ultrasonic supports are arranged on the high-voltage side of the long-shaft surface of the transformer body and two short-shaft surfaces of the transformer body; 6 ultrasonic transducers are arranged in the ultrasonic supports which are mounted and fixed through the ultrasonic transducer supports on the inner wall of the oil tank; 3 vibration transducers are arranged on the upper clamping piece and the lower clamping piece; and an HFCT (High Frequency Current Transducer) is arranged on the iron core in the transformer body at the position where a ground wire is arranged. The transformer adopting the structure further improves the sensitivity and effectiveness of the online monitoring, and also improves the safety operation level.