The present invention discloses a switching control circuit for a primary-side controlled power converter. A voltage-waveform detector produces a voltage-feedback signal and a discharge-time signal. A current-waveform detector generates a current-waveform signal by measuring a primary-side switching current. An integrator generates a current-feedback signal by integrating the current-waveform signal with the discharge time. A time constant of the integrator is correlated with the switching frequency, thus the current-feedback signal is proportional to an output current of the power converter. A PWM circuit controls the pulse width of the switching signal in response to the outputs of a voltage-loop error amplifier and a current-loop error amplifier. The output voltage and the maximum output current of the power converter are therefore regulated.