Resistivity can reflect the deterioration condition of insulation materials. This paper mainly focuses on the indirect resistivity detection of solid insulation materials such as oil-impregnated paper inside power transformers. In order to obtain accurate detection results

solid insulation materials inside transformer are divided into several regions

and the differences in resistivity values between different regions are used to approximately represent the non-uniform distribution of resistivity caused by non-uniform deterioration of material. On this basis

the mathematical relationship between insulation resistance parameters of transformer and the resistivities of different regions is discussed. Moreover

a multiregion indirect detection method for resistivity of oil-impregnated paper based on support vector machines（SVR） is developed accordingly. The proposed method is verified with 10 kV oil-immersed distribution transformers. Region division is conducted according to the types of materials

and it is found that the indirectly detected resistivity of 0.5 mm paperboard is close to the measurement resistivity of corresponding test object with a relative error of 12.5%. The proposed method can provide resistivity detection results of solid insulation materials at different regions inside power transformer

which can help to promote the operation and maintenance level for power transformer.