A timing generator and a timing signal generation method for a power converter are provided. The timing generator includes an adjusting circuit and a timing generation unit. The adjusting circuit receives an error signal related to an output voltage of the power converter. The adjusting circuit generates an adjusting signal according to the error signal and a delay circuit. The timing generation unit generates a timing signal according to the error signal, the adjusting signal and a control signal. A width of the timing signal is changed with the error signal and the adjusting signal. Accordingly, the timing generator adjusts On-time/Off-time in response to a transient response.