A process for producing high speed transmitting dielectric materials comprises essentially mixing and reacting a proportion of polyphenylene ether (PPE) with a proportion of an epoxy resin of the type of low bromine content in a non-polar solvent in the presence of a catalyst in a reactor at a temperature of 90.degree. C. to 220.degree. C., characterized in that, in the course of the reaction, PPE needs not to be cleaved into small molecules and in stead, can mix and react directly with the epoxy resin to thereby produce a high speed transmitting dielectric material. The process of the invention can reduce greatly the synthetic reaction time, and is applicable in the production of the material useful in printed circuit board for wireless communication, base station and the like.