The invention discloses a reservoir monitoring device based on solar energy, which comprises a power supply part, a rainwater collection part is fixedly connected to the top end of the power supply part, a rainwater storage part is arranged below the rainwater collection part, the rainwater collection part and the rainwater storage part are correspondingly arranged, and a shielding part is arranged on one side, far away from the rainwater storage part, of the power supply part; the side, close to the rainwater storage part, of the power supply part is fixedly connected with supporting legs, a backflow box is arranged below the rainwater storage part, a gravity box is arranged below the backflow box, the backflow box communicates with the gravity box through a hose, the rainwater storage part and the backflow box are both fixedly connected with the supporting legs, and the gravity box is slidably connected with the supporting legs. According to the invention, the solar panel can absorb solar energy and convert the solar energy into electric energy to be stored so as to be used by a monitored electronic device when there is no rainfall, and the solar panel can be protected and the rainfall can be monitored when there is rainfall, so that the service life of the solar panel is prolonged, and the use purposes of the monitoring device are increased.