Lead-free piezoelectric 〈001〉-oriented KNN crystals each with a dimension of 5 mm3 mm1 mm are obtained by melt grown technique. The room temperature crystal structure of orthorhombic perovskite-type lattice is determined from XRD measurment. The SEM observation reveals the growth steps aligning approximately along the 001 direction. Base on the model of negative ion coordination polyhedrons, it is explained that the layer growth mechanism is dominant for the 〈001〉 face. Two phase transition temperatures of orthorhombic-to-tetragonal (O-to-T) and tetragonal-to-cubic (T-to-C) are around 240 ℃ and 405 ℃ for KNN crystals according to the dielectric measurements, respectively. A linear fitting of the modified Curie-Weiss law to experimental data shows that the normal ferroelectric property is dominant for KNN crystal.