The crystal of high concentration Nd:YAG was grown by flux method and diode pu mp microcavity laser was studied.High efficiency and frequency solid state lase r was built on research and development.some applications such as target designa tion,laser radar,rangefinder,CATV etc. In order to maximize pump efficiency and power output,the Nd concentration shoul d be made as high as possible without degrading the gain through concentration q uenching.In crystal grown by Czochraski method.it is difficult to increase the N d concentration over 1.2% because of Nd segregation in the melt (yttrium aluminum garnet),which leads to large nonuniformities in doping.However,by using the f lux met hod growth technique,it is possible to grow uniformly doped crystal as much as 4 % Nd concentration YAG.