The invention provides a power-on reset circuit and a power supply device. The power-on reset circuit comprises an overvoltage detection unit and a timing unit, wherein the overvoltage detection unitis connected with a voltage output end of the power supply and is used for generating an overvoltage indication signal when the voltage output by the voltage output end is detected to be larger than or equal to a preset voltage; and the timing unit is connected with the overvoltage detection unit and is used for starting timing when the overvoltage indication signal is received and generating a power-on reset marking signal after the timing time is elapsed, wherein the timing time can be adjusted. According to the power-on reset circuit and the power supply device, timing can be directly started when the overvoltage indication signal S1 is received through the timing unit arranged at the rear end of the overvoltage detection unit, so that an external microcontroller does not need to perform controlling, and it does not need to start to work before the power supply is powered on; besides, the timing time can be adjusted according to actual conditions, and the work is flexible and convenient.