Leed titanate as an ionic Perovskite is ferroelectric at the lower of the below 766 K, which is called the transition temperature (Curie temperature), and at the above of this temperature is in the paraelectric phase. Studying the influence of mechanical parameters on the ferroelectric properties of PbTiO3 is important in the industrial application (such as RAM) of PbTiO3. In this study, using the molecular dynamics simulation method, the stress-strain effects on the polarization of lead titanate in the ferroelectric phase have been investigated. For modeling the atomic potential and interactions between ions in the ferroelectric phase, the short-range Buckingham potential and long-range coulombic potential, and, in addition, the fourth-order potential of oscillatory springs using a shell model (a model for calculating the polarization of a system) has been used. In this study, the effects of mechanical stress-strain action in the ferroelectric phase were investigated in two tensile and compression uniaxial stress-strain. In tensile stress-strain mode, the application of external stress leads to an increase in the polarization of the system, while applying compression stress-strain results in the decrease of the polarization of the system, so that by applying stress-strain, the polarization of the system reaches zero.