When incident fundamental wave and frequency-doubling wave were fitted to quasi-phase matching, with diode-pumped Q-switched 1342-nm Nd∶YVO4 laser, generations of red light at 671 nm and blue light at 447 nm in a periodically poled LiTaO3 (PPLT) were demonstrated. Principles of frequency-doubling and sum-frequency were applied in the course. Temperature of PPLT was modulated in order to accomplish quasi phase matching. When average power of 1342-nm fundamental wavelength was 1.58 W, the maximum average power of red light (671 nm) was 750 mW with corresponding matching temperature of 92.3℃ and temperature of full wave half width of 3.2℃, and the maximum average power of blue light (447 nm) was 128 mW with matching temperature of 83.2℃, temperature of full wave half width of 4.5℃. The optical-optical conversion efficiency of red light was 47.4% and that of the blue light was 8.1%. Output powers of red light and blue light were stable by double-frequency and sum-frequency in a PPLT for a longer time. These results indicated that PPLT may be used to construct an all-solid-state red and blue dual-wavelength laser.