High efficiency SRS (Stimulated Raman Scattering) in high pressure H2 was exited by YA.G SHG laser. Two orders of Stokes output and six orders of anti-Stokos output have been obtained and the corresponding wavelength ranges from 0.229 to 1.58 micron. The influences of interaction length and beam focusing on the threshold and the conversion efficiency is presented in this paper. Explanation of the experimental results is given.