This standard describes a method for determining the electrical conductivity of an aqueous solution obtained by extracting epoxy resin with water at 95°C. The method is specifically applicable to epoxy resins that can melt at the extraction temperature, and it is particularly critical for evaluating epoxy resins used as insulating materials in electronic devices. The electrical conductivity of the water extract reflects the content of ionizable impurities in the resin, which directly affects the electrical insulation performance of the material. This standard is equivalent to the international standard ISO 21318:2007. The core detection instrument is a laboratory conductivity meter capable of accurately measuring the conductivity of solutions. Additionally, a constant-temperature water bath or oil bath with precise temperature control is required for extraction at 95°C, along with equipment for preparing distilled or deionized water that meets the requirements to ensure low background conductivity of the experimental water.