The invention discloses a method for preparing a KTP
crystal capable of resisting gray track, comprising the following steps that: 1) KH2PO4 and TiO2 as raw materials used to synthesize a KTiOPO4
crystal, and K2HPO4 as the
raw material used to synthesize a K4P2O7(K4)
solvent are mixed according to a certain ratio, and the initial growth mol ratio of the KTiOPO4 to the K4P2O7 obtained after the
chemical reaction is about 0.8; 2) the mixed raw materials are put in a
platinum crucible and the solution filling amount is between 75 and 85 percent; 3) the
platinum crucible is put in a furnace body, a
temperature gradient of the furnace is set to be between 3 and 8 DEG C per 10 centimeters, and the furnace is heated so that the raw materials are melted and react to form an even and stable high temperature solution; and 4) the
seed crystal is put in the high temperature solution, the temperature is reduced at a
temperature gradient of between 1 and 8 DEG C per 100 hours, and the KTiOPO4
crystal is grown at a temperature interval of between 850 and 820 DEG C. The method utilizes the K4P2O7
solvent to prepare the KTP crystal, reduces the absorption coefficient of the KTP crystal, and has evident anti-gray track performance; therefore, the frequency multiplication conversion efficiency of the KTP is improved further, the KTP crystal has good
voltage withstanding and modulation performances and can be used as an electrooptical crystal.