Design of 808 nm epitaxial layer structure is demonstrated, and a very low internal loss less than 0.5 cm-1 is achieved. The quasi-continuous wave (QCW) high peak power 808 nm laser bar is fabricated with this high efficiency wafer. The bar with a filled factor of 85%, emitter number of 60, emitting width of 140 μm, and cavity length of 2 mm is measured at QCW mode. The peak power is 613 W with a slope efficiency of 1.34 W/A (drive current of 500 A, pulse width of 200 μs, repetition frequency of 400 Hz, duty ratio of 8%). The peak wavelength is about 807.46 nm with a spectral half-width full-maximum of 2.88 nm. The lifetime test is also demonstrated at QCW 300 W (8% duty ratio), the lifetime of five bars is all above 3.63×109 shot, the current fluctuation is lower than 10% at the constant power of 300 W, which satisfies commercial application requirement.