Abstract: An attempt has been made to study the photo dielectric effect in mixed lattice of (Al2O3-ZnS) Cu, Cl with different proportion .The mixed lattice of (Al2O3-ZnS) Cu, Cl were prepared by heat treatment technique taking firing temperature 8200C at 45 minute. Polystyrene was used as binder for sandwitching sensitive material in form of parallel plate capacitor .The measurement were carried out in frequency range (100 Hz -50 Hz) with illumination of intensity up to 5000 lux and for temperature range between 400C to 900C. The capacitance (C), conductance (G) and loss factor (tan) were measured under various parameters, such as field intensity, intensity of illumination and temperature of sample.