Abstract: In order to improve the research efficiency of substitutes for SF₆, structure-activity relationship between microscopic descriptors and insulation strength of gaseous molecules is necessary to be analyzed. Based on the density functional theory, the M06–2X method with 6-311++G(d, p) basic set is used to calculate the structural parameters and the GIPF parameters at multiple electron probability density isosurfaces for 72 kinds of molecules. Correlation coefficients of different parameters with the insulation strength are analyzed, and the model for predicting insulation strength is presented. The molecular weight, the polarizability in the structural parameters and the molecular volume, the total surface area, the positive potential surface, the non-polar surface area, and the polar surface area in the GIPF parameters all are strongly correlated with relative insulation strength. The structural parameters are not affected by the value of electron probability density. However, the correlation of GIPF parameters varies widely at different electron probability density isosurfaces. Most of the GIPF parameters have the strongest correlation with insulation strength at 3.374 nm^–3~33.742 nm^–3 electron probability density. The prediction model is built based on GIPF parameters at 10.123 nm^–3 electron probability density isosurface, and the determination coefficient is 0.762 with a mean squared error(MSE) of 0.119. After taking the polarizability α into consideration, the model determination coefficient is 0.801 with a MSE of 0.099 at 16.871 nm^–3 electron probability density isosurface. The prediction accuracy of insulation strength can be effectively improved by stratifying the electron probability density, and combining the structural parameters with the GIPF parameters.