In view of the shortcomings of theoretical calculation on magnetic shielding performance, a theoretical calculation method of magnetic shielding performance based on radial basis function (RBF) neural network is proposed. First of all, the control variable method is used to separate the independent parameters. And the independent parameters are modeled independently. Then, the finite element numerical method is used to obtain training data by Ansoft Maxwell software. And the training data is used to train RBF neural network to model the non independent parameters. Finally, the independent parameters model and the RBF neural network module are combined to obtain magnetic shielding factor calculation model of the magnetic shielding device. Taking the magnetic shielding factor calculation of the rectangular magnetic shielding device as an example, the simulation results show that the fitting results of the calculation model are consistent with those obtained by numerical calculation. The maximum relative error between the model calculation results and the numerical calculation results is 10.3%, and 95% of the relative error is less than 8%. Compared with the traditional analytic method, it is more close to the accuracy of the numerical method and is more suitable for engineering estimation.