Shell model potential is widely applied to molecular dynamics simulations of ionic crystal, and the parameters of shell model potential function are crucial to the simulation veracity. The parameters of shell model of multi-oxide are numerous, and the optimization is a challenging task. In this paper, the sensitivity analysis is applied to find the key parameters which affect structure and properties mostly in all the shell model potential parameters of BaTiO3. Whereafter, the genetic algorithm is applied to optimize the key parameters, and the insignificant parameters are kept constant in optimization. The results show that the structures, physical properties and phase transition of BaTiO3 simulated by the optimized potential agree well with the experimental data.