Photoinduced second harmonic generation is observed in CuI microcrystallite doped glass prepared by the sol-gel process when the glass has been irradiated with intense 1.06 μm and frequency doubled laser beams from a mode-locked Nd∶YAG laser. The signal is verified to originate from a second-order nonlinear process by the dependence of the singal intensity on input power. It is found that the signal intensity increases with the irradiation time and gradually approaches saturation. The effect may be explained reasonably by the DC field model.