What correlated inputs from the two eyes are responsible for mediating the critical period plasticity in developing V1 remains unclear. Using <em>in vivo</em> whole-cell recording from the mouse V1, we demonstrate that the coincidence of binocular synaptic inputs from the two eyes is a hallmark of the critical period and serves as neural substrates for the induction of experience-dependent ocular dominance plasticity of the developing V1, through a homeostatic synaptic learning mechanism.