Disclosed is an apparatus and method for controlling maximum power point tracking (MPPT) of a photovoltaic system using active power control. The apparatus includes a photovoltaic panel, a photovoltaic inverter unit which converts direct current (DC) power received from the photovoltaic panel into alternating current (AC) power and outputs the AC power used as commercial power, and an active power-based inverter control unit which determines a reference value (Pmpp) for output power (Pinv) of a photovoltaic inverter using a curve (Pmpp) connecting maximum power points according to a change in solar irradiance in a P-V curve showing a relationship between photovoltaic output power and a terminal voltage and measures a terminal voltage (Vpv) of the photovoltaic panel to allow the photovoltaic inverter to perform an operation according to MPPT control for tracking a value of the terminal voltage changed according to the solar irradiance.