The disclosure provides a digital-to-analog conversion device and an operation method thereof. The digital-to-analog conversion device includes a digital-to-analog conversion circuit and a slew rate enhancement circuit. The digital-to-analog conversion circuit is configured to convert a digital code into an analog voltage. An output terminal of the digital-to-analog conversion circuit outputs the analog voltage to a load circuit. A control terminal of the slew rate enhancement circuit is coupled to the digital-to-analog conversion circuit to receive a control voltage following the analog voltage. The slew rate enhancement circuit is coupled to the output terminal of the digital-to-analog conversion circuit. The slew rate enhancement circuit enhances the slew rate at the output terminal of the digital-to-analog conversion circuit based on the control voltage.