Superconducting thin films of FeSe0.5,Te-0.5 are epitaxially grown on piezoelectric 0.71Pb(Mg1/3Nb1/2)O-3-0.29PbTiO(3) (PMN-PT) single-crystal substrates. Upon the application of an electric field to the PMN-PT along the thickness direction the superconducting properties of the FeSe0.5,Te-0.5 films, such as the normal-state resistance, superconducting phase transition temperature, upper critical field, critical current, and coherence length are in situ modified via the ferroelectric polarization rotation, converse piezoelectric effect, and structural phase transition of the PMN-PT. Our findings demonstrate that the combination of superconducting thin films with piezoelectrically active PMN-PT offers a promising approach for exploring the intrinsic lattice strain effects of iron-based superconducting systems.