Oil-paper insulation structure equipment often has yellow waxy deposits when it disintegrates. It is called X-wax because it does not have a fixed chemical formula. X-wax will generate a large amount of gas during the formation process. After formation, X-wax will adhere to the insulation paper and enter the pores to increase the dielectric loss, resulting in an increase in overall loss and a rise in local temperature. However, there is no detailed report on the mechanism of X-wax production. Based on molecular dynamics, the first step of the X-wax production process is simulated:the generation of free radicals, and a mineral insulating oil simulation model containing 30 molecules is established. The free radical generation in the oil model is simulated based on the ReaxFF force field at 473 K, 393 K and 373 K and the first free radical generation at each temperature with the generated trajectory file is captured. During the simulation process, it is found that the carbon-hydrogen bonds on the naphthenes are easily split into two free radicals, and the recombination between the macromolecular radicals could form X-wax, and the hydrogen radicals interacted to generate hydrogen. Through the analysis of the temperature curve, it is found that within the simulated temperature range, the free radical generation rate and temperature are positively correlated.