A temperature adaptive audio amplifier device includes a digital analog convertor, a gain controller, an amplifier, a temperature sensor and a decision circuit. The digital analog convertor transforms a digital audio signal into an analog convertor. The gain controller includes a gain value and is configured to perform gain processing on the analog audio signal and generate a gained analog audio signal. The amplifier is configured to amplify the gained analog audio signal and generates an amplified analog audio signal. The temperature sensor generates a temperature detect signal according to a junction temperature of the amplifier. The decision circuit receives the temperature detect signal and generates an adaptive gain adjustment signal to the gain controller. The adaptive gain adjustment signal is used to adjust the junction temperature of the amplifier to be within an upper temperature threshold and a lower temperature threshold.