Abstract: It is important for optimization design of transformer insulation that the spatial electric field distributes in the oil under the impulse voltage. Existing design methods do not take into account temperature and space charge migration effects. In order to study the effect of temperature on the space charge migration characteristics in the oil, an electric field measurement platform under impulse voltage was built, the temperature of the measuring platform can be controlled. The spatial electric field distribution in the oil with uniform electric field at 25℃, 50℃ and 60 ℃ under lightning impulse voltage was measured. The results show that as the temperature increases, the peak electric field strength at 60 ℃ has decreased by 5.2% compared with it at 25 ℃, the field strength distribution in the oil reaches the stable stage at 0.60 μs under 50℃, the maximum electron drift velocity and mobility is 1.8 and 2.0 times at 25 ℃. The increase in electron mobility and drift velocity caused by temperature primarily generates the above phenomenon. The results of this paper provide experimental basis for transformer insulation optimization design.