We experimentally demonstrated an electrically controlled focus-variable optical system by cascading two lenses,which were made of polymer dispersed liquid crystal (PDLC) with a hole-type electrode.Upon application of an external electric field,spatial distribution of refractive index was achieved inside PDLC cell,which can be functioned as a focusing lens.The focus length of such a PDLC lens can be effectively changed by adjusting the amplitude of the electric field.The experimental results showed that when the applied AC voltage was increased from 0 V to 80 V,the focal length of single lens decreases from ∞to 1.073 m,and that of the double cascading lenses from ∞to 0.484 m.These experimental results were in good agreement with the simulation results.Such a PDLC tunable lens had a response time of less than 1 ms,which could benefit many fast imaging applications in future.