Abstract: In order to reduce the driving voltage of an electro-optical switch,a LiNbO3 crystal was placed in a Fabry-Perot cavity and the transmissive characteristics of this Fabry-Perot electro-optical switch was investigated experimentally.The results showed that the driving voltage of the Fabry-Perot electro-optical switch was ~580V,which was much lower than the half-wave voltage of an electro-optical switch used as orthogonal polarizer,~2.1kV.Moreover,the rising time of the Fabry-Perot electro-optical switch,128μs,was shorter than that of a switch used as orthogonal polarizer,284μs.Theoretical analysis of transmitted characteristic dependence on driving voltage was performed,and the results were in accordance with the experimental results.