Abstract: The linear extrapolate method that widely used to calculate the range of electron has some shortcomings in the calculation and application. In the reference document, the range was defined as the thickness of shielding media, where relative intensity is 0.01. First, the modification to the numerical method of the reference document was given, and then a new calculation method for electron range was given. The range of electron was counted directly by direct Monte-Carlo method, whereas electron fluence was not concerned. The new method can easily calculate the range of electrons with various energies, without the restriction of thickness of shielding media. The calculation precision and efficiency of new method are very good. It also can provide the confidence interval of range.