All-solid-state single frequency 1064 nm lasers with long pulse, high repetition rate, high energy and high beam quality are designed by using seed injection and MOPA (Master Oscillator Power Amplifier) construction.100 μs pulse width, 500 Hz repetition rate, 700 mJ single pulse energy, M2=2.8beam quality single frequency 1064nm lasers are achieved when 0.7 mJ single frequency seed light is injected into a three-stage MOPA construction.On this basis, the research on the long pulse lasers frequency doubling is carried out.Theoretical calculation of the conversion efficiency is done by designing and optimizing the LBO (lithium triborate) crystal, which resulted in M2=1, ηmax=68%, M2=3,ηmax=33%.The generation of 212 mJ green light with the repetition rate as high as 500 Hz is obtained from a fundamental power of 700 mJ.The experimental conversion efficiency reaches to 31% and the power stability is better than ±1%.