The invention provides a full swing voltage conversion circuit. The full swing voltage conversion circuit comprises: an input terminal for inputting a first level signal; an output terminal for outputting a second level signal; a differential input unit for inverting the first level signal of the input terminal, and outputting a differential input signal; a conversion unit; and an output driving unit; wherein the full swing voltage conversion circuit further comprises an auxiliary pull-down unit between the input terminal and the conversion unit for receiving a feedback to improve capability of the conversion unit in recognizing the differential input signal, such that the full swing voltage conversion circuit of the invention can convert from inputting a low voltage to outputting a high voltage.