Abstract: By theoretical analysis method, this paper uses jet flow central axis flow velocity test deduce formula of single horizontal submerged jet under pure water state to calculate the central axis maxim flow velocity of different flows. By using FLUENT fluid calculation software, researching single horizontal submerged jet numerical simulation to get the central axis maxim flow velocity of related flow and to compare with the theoretical result, this paper verifies the feasibility and veracity of CFD flow calculation software to submerged jet research.