The utility model discloses a high-voltage circuit breaker equipped with a permanent magnet synchronous motor operating mechanism. The high-voltage circuit breaker comprises an arc extinguishing unit,a transmission system and a driving device. The arc extinguishing unit comprises a three-phase porcelain sleeve, the three-phase porcelain sleeve comprises an upper porcelain sleeve, a lower porcelain sleeve, a static contact and a moving contact, and the upper porcelain sleeve and the lower porcelain sleeve form an insulating chamber used for opening, closing and insulating the static contact and the moving contact. The driving device comprises a power module, a motor and a connecting device, the power module supplies power to the motor, and the motor drives the connecting device and drivesa rotating wheel of the transmission system; the transmission system comprises a transmission case, a runner, an output pull rod, a plurality of connecting rods and an insulating pull rod; the outputpull rod is driven through the rotation of the rotating wheel, the output pull rod drives a plurality of connecting rods of the transmission system, the plurality of insulating pull rods are driven through the horizontal displacement of the plurality of connecting rods, the mechanical linkage of the moving contacts of the A-phase porcelain sleeve, the B-phase porcelain sleeve and the C-phase porcelain sleeve in the vertical direction is driven, and the opening or closing is realized.