The X-ray diffraction (XRD) and scanning electron microscopy (SEM) study was carri-ed out for an amorphous Cu+ conductor 0.4CuI-0.3 Cu2O-0.3P2O5 with the simultaneous conductivity measurement in the isothermal heat treament process. The results indicated that the initial amorphous material was phase-separated. In the course of time, the separated amorphous phase disappeared, the crystalline γ-Cul and Gu2P2O7 formed in sequence and grew up gradually. The correlation of the phase separation and crystallization behavior with the con-ductiyity anomaly confirmed again the interface effect between different phases in amorphous fast ionic conductors and its universality.