Efficient second harmonic generation from pulsed parametric laser to 427-470 nm has been obtained in a KNbO3 crystal of in 1.5 mm length, by angular tuning at room temperature. The energy conversion efficiency is over 40%, Single pulse blue light z-eaohes 60 kW in peak power. Angular dependence of phase matching wavelength, the relation between conversion efficiency and fundamental intensity and acceptable angular phase mismatch are studied and discussed.