The gas-solid-liquid three-phase model based on the volume-average method was used to study the influence of process parameters upon the chromium element distribution and its uniformity in laser-cladded 316L stainless steel on 45 steel. First, the chromium elemental distribution in cladding layer was characterized by average concentration of chromium element and the evolution of chromium element distribution during the cladding process was analyzed; secondly, the simulated and experimental Cr distributions along y direction were compared to verify the model''s reliability. Then, a simulation was performed by set the orthogonal-process parameters to obtain the relationship between the process parameters and the distribution of chromium element in the cladding layer. Finally, according to the simulation results, the flow behavior of the molten pool was analyzed to obtain the relationship between the process parameters and the uniformity of chromium element in the cladding layer along the x direction. The result shows that the powder-feeding rate has the greatest influence on chromium content in the cladding layer, followed by laser power and scanning speed in sequence. The powder-feeding rate is positively related to the average concentration of Cr, whereas the laser power is negatively related to this concentration. The solidification and flow rates of the molten pool have an important impact upon the uniformity of the chromium element distribution in the cladding layer. A cladding layer with a more uniform elemental distribution can be obtained by appropriately increasing the laser power and reducing the scanning speed.