The invention discloses an automatic opener of a bottle cap, belonging to the application field of daily life. The automatic opener of a bottle cap comprises a case (1), a power switch (2), a master control unit (3), an actuator element system (4) and a measurement feedback element (5), wherein the actuator element system (4) is composed of an inner part and an outer part; the inner part is composed of a small motor, an inner dowel bar and a bottle cap grasping element, the inner dowel bar is installed in the output shaft of the small motor, the bottle cap grapping element is installed on the tail end of the inner dowel bar, and the outer part is composed of an outer dowel bar and a bottle body grasping element installed on the tail end of the outer dowel bar. The system has simple structure, is convenient to operate and has wide application, solves the problem of the field of automatically opening beverage bottle caps, and provides great convenience for plastic bottled beverage merchants and wide customers.