The invention discloses a novel electronic material with high thermal stability and a preparation method thereof and belongs to the field of high molecular materials for electronics. The preparation method comprises the following steps: Firstly, after carrying out chain expanding on nano silicon dioxide through polyacrylic acid, mixing with tetraethylenepentamine and polyethylenimine to prepare aminated nano silicon dioxide; then grafting the nano silicon dioxide with an epoxy group under the action of isocyanate; then grafting a flexible chain section containing hydroxyl on the nano silicon dioxide grafted with the epoxy group under the action of alkaline amine, so as to prepare modified nano silicon dioxide; finally, mixing epoxy resin, filler, a diluting agent, the aminated nano silicondioxide, the modified nano silicon dioxide, epoxidized soybean oil and a catalyst to prepare the novel electronic material with high thermal stability. The novel electronic material with high thermalstability, prepared by the technical scheme, can have very good utilization performance under a high-temperature condition.