10 picosecond pulses from a colliding pulse mode- locked Nd : YAG laser pass through a KTP crystal and pump DMSO Raman medium. The effect of lenses with different focal length, focal point location and the length of Raman medium on the transient stimulated Raman scattering studied experimentally. Energy conversion efficiency of 45.6% and 10.5% for the forward and backward first Stokes Raman sacttering are obtained respectively. The experimental results are discussed.