A vegetable oil paper insulation state evaluation method based on a fractional Zener model comprises the following steps of firstly, deriving the fractional Zener model by utilizing a fractional calculus theory, and establishing a relational expression suitable for vegetable oil paper insulation system fractional Zener model parameters and frequency domain dielectric spectrum characteristic quantity complex dielectric constants; identifying parameter values of the score Zener model respectively; calculating a complex dielectric constant real part theta 'and a complex dielectric constant imaginary part theta ', introducing a concept of coincidence degree, comparing a complex dielectric constant calculated value with a measured value to find that the coincidence degree of the complex dielectric constant calculated value and the measured value is high, and enabling a low frequency band to have higher accuracy, which indicates that the fractional Zener model is suitable for describing therelaxation process of vegetable oil paper; selecting appropriate model parameters a, shape parameters and relaxation time as characteristic quantities for evaluating the aging of the vegetable oil paper insulation system, and establishing a functional relation between the model parameters and the acid value in the oil. According to the method, the fractional order theory is applied to the relaxation process of the dielectric medium, it is found that the fractional Zener model carries more effective information in the test sample, and therefore the aging state of the vegetable oil paper insulation system is evaluated more accurately.