A current limit protection apparatus and a method for current limit protection are provided. The current limit protection apparatus includes a MOS transistor, a current detecting unit, and a current limit circuit. Two source/drain of the MOS transistor are used for receiving a first-voltage and outputting a second-voltage respectively. A gate of the MOS transistor is used for receiving a gate driving signal to determine a conducting current of the MOS transistor. The current detecting unit is used for detecting the conducting current, so as to generate a detecting result. The current limit circuit has a plurality of current threshold values. The current limit circuit selects one of the current threshold values according to an indicating signal and generates the gate driving signal according to a difference between the selected current threshold value and the detecting result.