A fixed dead time PFC controller, comprising: an amplitude normalization circuit, used to generate a normalized signal according to a full-wave rectified input voltage; a comparator circuit, used to compare the normalized signal with a threshold voltage to generate a select signal, wherein the select signal exhibits a first state when the normalized signal is higher than the threshold voltage, and a second state when the normalized signal is lower than the threshold voltage; and a driving signal selection circuit, having a first input end coupled to a first driving signal, a second input end coupled to a second driving signal, a control end coupled to the select signal, and an output end for outputting a gate driving signal.