Abstract: Determination of neutral plane position is the key issue in the analysis of bonded two-layered slab on a Winkler foundation, however, there exist no theoretical formulas and solving methods for the problem when the Poisson’s ratios of two slabs are different. Based on the Kirchhoff’s hypotheses, the equation of neutral plane was formulated and numerical method was employed to solve the equation and obtain the curve of neutral plane. In addition, the effects of response modulus of foundation, the ratio of Poisson’s ratios, elastic moduli and thicknesses on the positions of neutral plane were discussed, and the results show that the response modulus of foundation and Poisson’s ratio plays important roles in the vicinity of load; the elastic moduli have a primary influence on the position of neutral plane, and the neutral plane shifts to the slab which has a greater elastic modulus; on the contrary, the thicknesses have little effect on the neutral plane.