This application provides a photovoltaic system and a maximum power point tracking control method for a photovoltaic system. The photovoltaic system includes an MPPT controller and a power converter, and the MPPT controller is connected to the power converter. The MPPT controller is configured to: be connected to a photovoltaic array, and track a global maximum power point MPP of the photovoltaic array. The MPPT controller may be further configured to obtain, when there is a periodic shade for the photovoltaic array, a multi-peak search start moment of global MPPT of the photovoltaic array based on a status of tracking the global MPP of the photovoltaic array in a target time period, so that when the multi-peak search start moment in each MPPT period arrives, the global MPPT of the photovoltaic array is started, to output a working point of the global MPP of the photovoltaic array to the power converter. According to this application, efficiency of obtaining the working point of the global MPP of the photovoltaic array can be improved, and precision of controlling the global MPPT of the photovoltaic array can be improved.