Abstract: A solar photovoltaic system includes a solar cell array, a bypass diode and a light-emitting module. The solar cell array has a positive terminal and a negative terminal and includes a plurality of solar cells connected in series. The bypass diode is connected to the solar cell array in parallel. The light-emitting module is connected to the solar cell array in parallel and includes a Zener diode and a light-emitting diode. The Zener diode has a cathode and an anode electrically connected to the positive terminal and the negative terminal of the solar cell array, respectively. The light-emitting diode is connected to the Zener diode in series. The light-emitting module has a threshold voltage which is a breakdown voltage of the Zener diode and related to a voltage of a maximum power of the solar cell array under a standard illuminance.