The frequency doubling properties of potassium lithium niobate crystals grown from melts with different content of Li 2O were studied by using quasi cw Ti:sapphire laser. The results showed that potassium lithium niobate crystal does not have nonlinear optical performance unless the Li content in the crystal reached a certain amount. The higher the content of Li in the crystal, the better the frequency doubling performance. The results of frequency doubling experiment of the potassium lithium niobate crystal grown from the melt with Li 2O 26mol% showed that the crystal can double the cw Ti:sapphire laser with the wavelength of 820~960nm so as to obtain the output of blue green beam. The crystal showed good second harmonic generation properties.