A driving circuit of an input/output (I/O) interface is provided. The driving circuit includes a main output stage and an enhancing unit. The main output stage receives at least one driving signal and outputs an output signal corresponding to an input signal accordingly. The enhancing unit is coupled to the main output stage. The enhancing unit receives and detects the level of the output signal so as to drive the output force of the main output stage in a first output level or a second output level, wherein the first output level is higher than the second output level.