A diode laser (DL)-pumped Nd:YAG all-solid-state sum-frequency laser is presented. Efficient sum-frequency mixing 1064 nm and 1319 nm in a 4 mm×4 mm×20 mm LBO crystal (x-cut, θ＝90°,＝0°) is obtained by extra-cavity sum-frequency. Type I noncritical-phase-match (NCPM) is realized by controlling the temperature of the LBO crystal. By injecting 1.23 W and 1.50 W of 1064 nm and 1319 nm Q-switched radiation into the LBO crystal, respectively, 500 mW of sum-frequency maximum output is generated with a pulse repetition rate of 500 Hz and pulse duration of about 25 ns, efficiency up to 18.5%, beam quality M2 less than 3. By carefully adjusting the tilt angle of etalon in each oscillator, the wavelength of sum-frequency output is tuned to the sodium D2 line.