The invention relates to an on-load voltage-regulating transformer voltage regulation structure provided with a bias field winding and belongs to the technical field of transformer manufacturing. According to the technical scheme, a bias field winding PV is added in a transformer column apart from a voltage-regulating winding TV, and number of windings of the bias field winding PV is equivalent to number of generated rated step voltage Us; both the bias field winding PV and the voltage-regulating winding TV are of spiral structures and perform winding individually and respectively; the bias field winding PV is divided into a bias field winding PV1 and a bias field winding PV2 which are equivalent in number of windings, namely half of that of the bias field winding PV, and the bias field winding PV1 and the bias field winding PV2 serially form the bias field winding PV through a lead. Since the bias field winding is added in the transformer column, the technical problems that tapping points and tapping leads of the on-load voltage-regulating transformer are too many in constant flux having multiple voltage regulating grades are solved, and security and reliability of the transformer are improved.