The invention discloses an all-digital phase-locked ring applicable to video signal processing, comprising an analog-to-digital conversion circuit ADC, an automatic gain control circuit AGC, a digital low-pass filter DLPF, a synchronous header split circuit, a frequency detector FD, a time-to-digital conversion circuit TDC, a coarse tuning filter, a phase detector PD, a fine tuning filter, a summator, a digital-controlled oscillator and a pixel frequency divider circuit. The phase detector, the time-to-digital conversion circuit, the coarse tuning filter, the digital-controlled oscillator and the pixel frequency divider circuit constitute a frequency locking loop circuit, and the locking process of the all-digital phase-locked ring is accelerated. The analog-to-digital conversion circuit, the automatic gain control circuit, the digital low-pass filter, the frequency detector, the phase detector, the fine tuning filter, the digital-controlled oscillator and the pixel frequency divider circuit constitute a phase locking loop circuit, and the phase locking loop circuit is used for accurately locking the phase of a synchronous header in an analogue video signal.