First principles calculations based on the density functional theory of the electronic structure,elastic and lattice vibrational properties of orthorhombic CaShO3 are carried out using standard functional approximation and density functional perturbation theory.The results show that CaSnO3 is an insulator with an indirect local density approximation and generalized gradient approximation gap of 3.10(2.69)eV.In addition,the Raman vibration modes of CaSnO3 are determined by the calculated phonon frequencies at the gamma point,where the prominent peaks of the Raman spectra of CaShO3 coinciding with the calculated frequencies can be assigned.