We investigated structural instability and polarization of BaTiO3/SrTiO3 superlattice under stress by using first-principles calculation. Our results show that stress induces lattice distortion and charge transfer between Ti atom and O atom. With stress increasing，atomic displacement in BaTiO3/SrTiO3 superlattice grows gradually，resulting in the enhancement of polarization. Furthermore，polarization of superlattice BaTiO3/SrTiO3 can be controlled by changing the stress.