A predictive dead time generating circuit includes a dead time detecting module configured to detect a dead time between the switching off of the upper power transistor and the switching on of the lower power transistor, and a dead time between the switching off of the lower power transistor and the switching on of the upper power transistor, and to generate a first detecting signal and a second detecting signal according to the condition of whether the detected dead time reaches an optimal value. The logic control module changes the output of the delay module according to the judgment result of the dead time detecting module, so as to change the dead time between the driving signal of the upper power transistor and the driving signal of the lower power transistor.