Based on the centrifugal law, sedimentation speed expression formulas of solid particles in spun-cast concrete were established .Comparing sedimentation speeds of steel fiber with coarse aggrgate and fine aggregate, location of steel fibers in spun-cast concrete was determined. From view of interaction principle of solid with liquid, the effect of centrifugal sedimentation function and shearing friction of viscous liquid on steel fiber arrangement is analyzed. Theoretical distribution rule of steel fiber in spun-cast concrete was determined. Combined with experimental study, the correctness was proved. Theoretical foundation has been laid for improving performance and expediting engineering application of spun-cast concrete.