In order to accelerate the fluid flow and enhance the optical sensitivity for liquid sensing application,a robust opened hole suspended core fiber configuration based on t he forward/backward Raman coupling detection mechanism is proposed and analyzed.A formula for forward/backward Raman coupling is utilized to study the dependence of Raman intensity on base materials and fiber size.The Raman signal intensity model is deduced based on the Raman scattering effect and waveguide theory.The field distributions,effective mode index,normalized overlap intensity (NOI),effective mode area and confinement loss are calculated .The results show that the final detected Raman signal intensity is not only determined by the overla p.T he effective mode area and transmission loss also play important roles.There is an optimized fibe r core size for exciting the maximum Raman signal intensity,while the optimized fiber core size is related with the fluidic refractive index.For silica-based fiber,the optimal fiber core ra dius region is around 150nm when the strut′s thickness is around 20nm－200nm.While with the increa se of fluidic index,the optimized core radius size is increased,while corresponding Ram an signal intensity is decreased.Besides,the Raman characteristics of closed hole suspended core fibe r and nanofiber are also compared with those of the proposed opened hole suspended core fiber.