A method for controlling an alternating current (AC) output of a photovoltaic (PV) device, and an AC PV device are introduced herein. The method includes: receiving solar radiant energy by using a PV cell array and then converting the solar radiant energy into a direct current (DC) energy output; and selecting an arrangement and combination sequence of the PV cells by using a control module, to vary a voltage according to a timing (frequency), so that a sine-like wave output is obtained at an output terminal.