Potassium tantalate niobate KTa_1-xNb_xO₃ (KTN) single crystals with different x values (x¼ 0, 0.25, 0.37 and 0.45) were grown by a top-seeded growth solution method in a KTa_1-xNb_xO₃ solid-solution system. The crystalline structure, optical and dielectric properties were investigated experimentally using X-ray diffraction, spectrophotometer and LCR meter, respectively. The compositions were measured by electron probe microanalysis. The band gap energy was calculated based on the optical transmittance spectra. The XRD results indicated that the single crystals exhibited cubic structure (x 0.37) and tetragonal phase (x¼ 0.45) at room temperature. The absorption properties demonstrated that the absorption coefficients and the band gap energy decreased with the increasing Nb component. The dielectric results indicated that the Curie point increased depending on the increasing Nb component.