The frequency-doubling properties of potassium lithium niobate crystals grown from melts with different content of Li₂O 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 Li₂O 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.