Polyimides are a kind of high-performance functional material which is widely used in various fields

but low refractive index limits its application in the field of optics. By introducing aromatic ring substituents

sulfur atom in the main chain and inorganic particles hybrid modification method many researcher can effectively improve the refractive index of the polyimides. This article describes the latest research progress both in domestic and overseas that some research team prepared high refractive index of the polyimides

then concludes that the method of increasing the refractive index of polyimide can be divided into the following ways:introducing sulfur atom into the main chain of polyimide; mixing the inorganic particles to modify the polyimide; developing a new synthesis route. The synthetic route of the several methods and the properties of the resulting products were reviewed and point out the general tendency of the synthesis of high refractive index polyimides.