According to the molar ratio of 0.71Pb(Mg 1/3 Nb 2/3 )O 3 -0.26PbTiO 3 -0.03Pb(Er 1/2 Nb 1/2 )O 3 , Er 3+ -doped PMNT polycrystalline material was prepared by two-step solid-state synthesis at elevated temperature. Er 3+ -doped PMNT relaxor-based ferroelectric crystal with size of φ25 mm × 100 mm was grown from the stoichiometric melts by vertical Bridgman method. In the ferroelectric crystal with perovskite structure, Er 3+ ions were doped into the crystal lattice via one composition of the ternary solid solution compound. The dielectric, piezoelectric and ferroelectric properties and up-conversion emission performance of Er 3+ -doped PMNT crystal wafers were investigated systematically. It is verified that Er 3+ -doped PMNT crystal presents the similar electrical properties to those of undoped PMNT crystal. Under the excitation of 980 nm, the crystal also exhibits a strong up-conversion fluorescence emission characteristic to Er 3+ ions doped in the medium, and the emission intensity will be enhanced after being poled.