With the increasing promotion of national energy conservation and emission reduction policies, hydropower, turbine power generation and wind power generation have developed rapidly, and various generators and motors are developing in the direction of high voltage and miniaturization. It is the key to reduce the volume of the motor at the same power, reduce the insulation size (including inter-turn insulation and main insulation) and increase the slot full rate. The reduction of insulation size is a contradiction with insulation quality and insulation reliability. Only a scientific and reasonable insulation structure can make the motor not only have excellent performance, but also meet the needs of larger power and smaller volume. The insulation thinning of high voltage motor can improve the heat dissipation capacity of main insulation, reduce the temperature rise of motor, and reduce the aging of insulation near copper wire caused by temperature rise. In addition, reducing the insulation thickness can increase the utilization rate of the slot, reduce the size of the motor under the same temperature rise, and reduce the copper consumption and mechanical energy consumption. High voltage motor insulation thinning is an important way to improve motor efficiency and reduce manufacturing costs, but to achieve insulation thinning, it is necessary to develop new high-performance insulation materials and optimize integrated insulation system, without reducing electrical insulation, aging and other properties of the premise of insulation thinning. Electromagnetic wire, mica tape with less glue, environmental protection epoxy vacuum pressure impregnation (VPI) resin and high resistance anti-halo material are studied, and integrated insulation system is optimized for systematic performance evaluation. The results show that the optimized 10 kV insulation system has the insulation thickness between turns 0.40 mm, the main insulation thickness 1.8 mm, the corona voltage ≥1.7 UN, and the electric aging life ≥350 h. At the same time, it has excellent electrical insulation performance and meets the technical requirements of high voltage motor.