It is experimentally and theoretically found that the uniaxial compressive stress (σ) can lead to the decrease of both the ferroelectric remanent polarization (Pr) and the coercive field (Ec) of <001>-oriented 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 crystal. With the increase of σ from 0 to −15 MPa at 50 °C, Pr decreases from 20.69 μC/cm2 to 17.30 μC/cm2 and Ec decreases from 2.19 kV/cm to 1.89 kV/cm, respectively. A numerical simulation based on a phenomenological Landau-Khalatnikov theory is used to plot the polarization hysteresis loop under σ. The result of numerical simulation agrees with the experimental observation very well. The research is useful for the application of ferroelectric devices in strain engineering.