Femtosecond laser in green band is usually generated by frequency doubling of Ti: sapphire femtosecond laser. However, the high cost of Ti: sapphire laser and poor stability of its solid system limit the application of femtosecond green laser. In this paper, the femtosecond seed source based on SESAM passive mode-locking and chirp (CPA) technology are used to generate 1 030 nm fundamental frequency light. After compression and frequency doubling, the 515 nm femtosecond laser with pulse width < 400 fs and average power >2 W is achieved. The femtosecond laser has the ability to switch the output of fundamental frequency light and frequency doubling light, and has the advantages of compact size, stable pulse, high conversion efficiency and good beam quality. It can be used as the light source of ultrafast laser processing system.