Abstract: The thermal electrical accelerated aging test was carried out on the main insulation of the low-resin epoxy mica tape of the stator winding of the generator with a rated voltage of 10.5 kV, and the change of partial discharge characteristic parameters during aging and the relationship with the residual breakdown voltage U were analyzed. The accelerated aging b temperature was 155 ℃ and the accelerated aging voltage was 15.75 kV. Partial discharge test was conducted every 500 and the U value was measured. Five characteristic parameters, maximum discharge capacity, average discharge capacity, b discharge frequency, slope, kurtosis, were selected for research. The calculation shows that the absolute value of Pearson correlation coefficient between these five characteristic parameters and U is above 0.98, and the absolute value of correlation b coefficient of discharge frequency is the largest (r=-0.996 9), followed by slope (r=-0.997 6). According to the U prediction b model fitted by multiple linear regression, R2=0.999 8, RMSE=0.151 5 kV, It shows that the proposed characteristic parameter combination can properly reflect the aging condition of main insulation, which can provide theoretical support and data reference and for on-line monitoring and residual life prediction of generator insulation.