The characteristics of backward Raman scattering and amplification based on two hydrogen Raman cells are investigated. Both cells are filled with high-pressure hydrogen. The first cell is used to generate the Stokes seed light, and the second cell is used to amplify the seed light. The Stokes energy is measured at different pump energies, and different pump distributions between the two cells. When the pulsed pump energy of first and second cell separately is 100 mJ, 175 mJ, a pulsed Stokes energy of 44.0 mJ can be generated, and the corresponding photon conversion efficiency is 28.6% . The rate equations are employed to simulate the amplification process, and the theoretical results are agree with the experimental results on the whole. When the pulsed energy of Stokes seed light is as much as or greater than the pump laser, the Stokes can still keep a constant increment according to the numerical simulation. Based on the simulation results, the Raman amplification method is proposed to realize multiple laser series synthetic output.