Abstract: To reveal the flow characteristics of Logistic and Generalized-Arc-Tangent production decline equations, the paper selects a special oil-phase relative permeability relation and deviates Logistic and Generalized-Arc-Tangent production decline equations and its corresponding water-phase relative permeability formula according to the derivation process of Arps production decline equation. The results show that the type of production decline is mainly determined by the characteristics of oil-water two-phase flows under the condition of maintaining formation pressure by water injection. The relative permeability relations of oil and water phases take the water saturations at the outlet as variables, which complies with the industrial standards of relative permeability relations and avoids the defects of the pseudo-relative permeability relations using the average water saturation as a variable during previous decline equation derivation. The actual applications in Qiuling oilfield and Block Wen-5 in Tuha oilfield show that the actual production is consistent with the results obtained from the production decline equation determined by relative permeability relations of oil and water phases, respectively