A wireless charger includes a wireless charging transmitter. The wireless charging transmitter includes a transmission antenna, a driving circuit, a transmission temperature sensor, and a controller. The driving circuit can output a charging signal in a fast charging mode initially. The transmission temperature sensor can detect a transmission temperature value of the transmission antenna. The controller can receive the transmission temperature value from the transmission temperature sensor. The driving circuit is can output the charging signal in a fast charging mode initially. When the transmission temperature value is greater than an overheat value, the controller can control the driving circuit to output in a slow charging mode.