Average output power more than 50 W, 1064 nm picosecond laser with three power amplifier systems (LD double-pass amplifier, LD double end-pumped amplifier and LD single end-pumped amplifier) is reported. When input 6.67 W picosecond seed pulse, power amplifier′s average power achieves to 53.7 W with optical-optical conversion efficiency of 30.07%, a pulse duration of 10.45 ps. By using of nonlinear crystal LBO for second harmonic generation (SHG) with high average power of 27.16 W, a repetition rate of 80 MHz, a pulse duration less than 10 ps, SHG efficiency higher than 50.58% are obtained. At premise of high SHG efficiency, the system guarantees against damaging SHG crystal, keeps uninterrupted running with stable power more than 8 h.