The invention discloses a light and efficient voltage-continuous type alternating current voltage regulator which comprises a casing. An iron core is installed in the casing, a winding is installed on the iron core, an adjusting disc is installed on the casing, a rotating shaft is installed on the adjusting disc, a cantilever is installed on the rotating shaft, a moving contact is installed on the cantilever, a plurality of main fixed contacts are installed on the adjusting disc. One auxiliary fixed contact is installed between every two random adjacent main fixed contacts except two main fixed contacts at the outermost end of an arc, the width of the moving contact is larger than an interval between one adjacent main fixed contact and one auxiliary fixed contact, each main fixed contact is connected with the winding respectively through one tap, and each auxiliary fixed contact is connected with one main fixed contact respectively through one resistor. An A terminal block, an X terminal block, an a terminal block and an x terminal block are installed on the casing, one end of the winding is respectively connected with the X terminal block and the x terminal block, the other end of the winding is connected with the A terminal block, and the moving contact is connected with the a terminal block through a flexible connecting line.