A slope compensation method and circuit for a peak current control mode power converter circuit is provided. Since the power converter circuit has a synchronous signal of a driven signal of enabling the first primary switch and the second primary switch, a triangular wave signal is generated. The driven signals of the first and second primary switches determine the ramp up time of the triangular wave signal. The triangular wave signal is added to one of the output DC voltage feedback signal of the corresponding power converter circuit that are used to compare with a current peak value of the voltage feedback signals. Therefore, a high level triangular wave DC voltage feedback signal that is higher than the DC voltage feedback signal is formed, and the switching noises do not effect comparing result of a PWM controller of the power converter circuit.