Abstract: Accuracy and predictive power of two global models to predict nuclear charge radius are significantly improved combined with the radial basis function(RBF) approach. The root-mean-square(rms) deviation of Skyrme Hartree-fock-Bogoliubov(HFB25) model is reduced from 0.025 to 0.018 fm, using 885 experimental data of the nuclear charge radius to leave-one-out cross validation, the rms deviation of a formula proposed based on the shell correction energies and deformation parameters given by the Weizäcker-Skyrme(WS*) nuclear mass model is reduced from 0.022 to 0.017 fm. For the latest 144 experimental data, the rms deviations of HFB25 and WS* models combined with RBF approach are only 0.015 fm. With the RBF approach, by studying the correction degree of prediction values of HFB25 and WS* models in the superheavy region, it is found that the correction degree of WS* model in the superheavy region can be kept within 0.1 fm, while the correction degree of HFB25 model in the superheavy region is more than 0.1 fm. This is very useful for analyzing model errors and further improving the prediction accuracy of nuclear charge radius.