In order to improve the photoelectric response and stability of 9-cis-retinal Langmuir-Blodgett (LB) films, this article investigated the effect of nanometer-sized inorganic particles on organic functional membrane. The LB film containing 9-cis-retinal protonated Schiff base and mixed with hydrophilic gold sol containing different sizes of gold particles (from 10 to 50 nn) prepared by reducing HAuCl4 with sodium citrate was deposited in a ITO electrode. After the ITO electrode was immersed in the gold sol, 8-10 layers of LB membrane of samples containing 9-cis-retinal PSB were deposited on it, and the photoresponse and stability with and without ultrafine gold particles were measured. After added ultrafine gold particles, it was found that the photocurrent and stability of 9-cis-retinal LB films could be increased greatly. The quartz crystal microbalance, cyclic voltammetry, and absorption spectrum methods have been used to study the mechanism of this effect.