Doping CuO in KNSBN crystal, Cu:KNSBN crystal was grown by Czochralski technique. The exponential gain coefficient, response time, self-pumped phase conjugate reflectivity and phase conjugate response time of the crystal were measured. The exponential gain coefficient of Cu:KNSBN crystal achieved 24 cm−1 and the response time was 1.2s. Self-pumped phase conjugate reflectivity could reach 65% and phase conjugate response time was between 3 to 5s. The inhabitation of Cu ions in KNSBN crystal was primarily investigated.