Abstract: Double diffusive convection in the fingering regime is a commonly observed phenomenon in the (sub-)tropic ocean. It often happens when both temperature and salinity decrease with depth in the upper water, and plays a significant role in the vertical mixing and transport of heat and salt. In this study, we conduct two-dimensional direct numerical simulations of oceanic double diffusive convection in the fingering regime for four different combinations of component properties. We focus on the transport behaviors and flow structures, and their dependences on the control parameters, especially the influences of the Prandtl and Schmidt numbers. Results suggest that the overall trends of the dependences of heat and salt Nusselt numbers and Reynolds number on the Rayleigh number do not change for different density ratio, but their absolute values decrease as the density ratio becomes larger. This influence of density ratio becomes weaker as the Lewis number, i.e., the ratio between the two diffusivities increases. The dependences can be described by power-law scalings. For most of cases, the dominant structures are slender salt fingers. For several cases with small Lewis number and large Rayleigh number, the dominant structures change to large rolls which is similar to the convection turbulence. The dependence of finger width on Rayleigh number matches the prediction of linear stability analysis. All these findings provide useful information for understanding oceanic double diffusive convection, and extending the experimental and numerical findings to real actual problems.