Shortcuts to adiabaticity can speed up an adiabatic process along a nonadia-batic route. Inspired by the shortcuts to adiabaticity, in this paper we propose a method for fast and stable splitting of atom in a double well based on ultracold atomic interferometers. Specifically, we firstly apply the variational approximation approach to solve the Gross-Pitaevskii (GP) equation in the mean-field approximation theory to derive the dynamic equation of the Bose-Einstein condensation. Then we use the inverse engineering to design the frequency of external potential, which enables fast splitting of ultracold atom in a shorter time. And this method avoids the final excitation.