A coupling analysis method is proposed for the transient deformation of engines’ connecting-rods. A radial base function neural network (RBFNN) with three layers is designed to reconstruct the two-dimensional oil film forces. Forces acting on the two ends of the connecting-rod are achieved through coupling equations for it. Further，finite element analyses of transient deformation for the connecting-rod are made through software ANSYS. Meanwhile，the validity of the proposed method is demonstrated. Numerical results show the maximum deformation of a rotary connecting rod occurs before or behind the bottom dead center at compression stroke when the two-dimensional oil film forces are considered.