Abstract: The investigations on violet and deep-UV nonlinear optical crystals over the last decade,including successes and failures,are discussed in this paper.Successes include the discovery of KBBF crystal which produces the shortest second harmonic output (184.7nm),and KABO crystal which has been successfully grown to centimeter size and is a promising candidate for the fourth and fifth harmonic generation of Nd∶YAG laser light.However,we were surprised that the SBBO crystal which has good linear and nonlinear properties lacks structural completeness.As a result,the crystal cannot be used yet.Although we have spent about ten years on this field,the search for deep-UV nonlinear optical crystals is still not satisfactory.In the near future we will make greater efforts to improve the quality of the crystals we have discovered and will continue to search for the new ones that can overcome the problems of existing crystals.