We demonstrate a 532 nm and 1 kHz picosecond laser amplifier which is made up of one home-made picosecond oscillator seed, a regenerative amplifier, two-pass amplifier, a main amplifier, and a frequency doubler. The green laser has a beam quality factor of 1.39 and 1.96 for tangential direction and sagittal direction, respectively, and the long-term stability root mean square (RMS) is less than 0.3%.