A solar power supply device includes a solar panel and a rechargeable battery. The solar panel is configured to collect and convert optical energy to electrical energy. The solar power supply device further includes an e-paper display unit, a charging connection connecting to a rechargeable device. A detecting unit detecting the charging state information of the rechargeable device via the charging connection, a light-operated unit detecting ambient illumination intensity, and a processing unit for controlling the e-paper display unit to display charging states information obtained from the detecting unit and the ambient illumination intensity detected by the light-operated unit.