The integration of the wireless power transfer (WPT) coils allows the transfer of energy gathered by the current transformer (CT) on the high-voltage side of transmission line to the online monitoring equipment on the low-voltage side. This integration eliminates the need for extra WPT coils, which are both easy to implement and space-saving, while ensuring the insulation distance. However, to the best of our knowledge, there is no comprehensive research on the influence of embedding coil on the insulating characteristics of insulator. In this work, the insulation performance of insulators with embedded wireless power transfer coils is analyzed, by using the finite element analysis software. The electric field distribution around the insulator containing different numbers and positions of embedded coils is investigated and the maximum value of the internal electric field strength is recorded as a critical assessment indicator. According to the simulation results, a strong electric field strength occurs in the air cavities on the top and bottom surfaces of the coils. It is recommended that a vacuum be extracted to eliminate air gaps during the actual manufacturing process.