Abstract: 107 series high-temperature submersible motors,which belong to small diameter motors,are developed according to the production practice of Zhong yuan oilfield.With design and optimization of the parameters,selection of materials and study of the adaptability with submersible pumps,little diameter series motors with outside diameter of 107mm and insulation grade of H-degree have been developed.The axial projected size of the units is ?112mm,and can be applied in liquid-lift from oil wells of which the well casing inside diameter of larger than 116mm and there are casing deformation,undergauge,scale formation and high temperature of 150℃.They can not only save oil recovery costs,increase oil production rate,but also create outstanding economic and social benefit.