Abstract: Optical guidings in Raman FELs are studied theoretically and calculated in this papers.We have performed a two-dimensional program(FELOG),which is used to study optical guidings without and with wave guide constructions.The numerical simulations include optical field forfile,opitcal field radius,filling factor,and equivalent index of refraction,etc.The simualated results from experimental parameters agree with experimental results well.And the factors that affect optical guidings are analysed and discussed.