Abstract: Laying duck raising and duck egg processing belong to traditional superior animal husbandry in China. Dirty surface of duck eggs will shorten storage time and increase subsequent cleaning cost. The bottom wire mesh is an important part of the furnished cage and is closely related to duck egg cleanliness. Aiming to solve the problem that the surface of duck egg shell is seriously polluted during the process of raising laying duck in the cascading cage-rearing equipment, the authors optimized the dimension parameters of the bottom wire mesh in this paper. Based on the analysis of duck egg movement on the bottom wire mesh, a kinematics simulation mode was developed to determine the appropriate range of the bottom wire mesh slope using dichotomy depending on whether duck eggs roll out of the furnished cage. The steeper the slope, the easier it was for the duck eggs to roll onto the conveyor belt. But if the slope was too large, the duck eggs might collide with the egg on the conveyor belt to cause damage. Meeting the above conditions, the appropriate slope value was chosen. According to the longitudinal spacing in bottom wire mesh, the lateral spacing in bottom wire mesh, the diameter in bottom wire mesh, the total deformation maximum and the mass of the bottom wire mesh, mathematical optimization model of the bottom wire mesh was established. The authors adopted an analysis method of 3 factors and 4 levels corresponding surface, and the dimension parameters of the bottom wire mesh were optimized based on the total deformation maximum response surface. The optimum solution in the results had the maximum area of the leakage hole in the bottom wire mesh. The finite element software ANSYS Workbench was used as the computing platform in this analysis. After optimization, the slope increased to 8.5°, the area of the leakage hole increased by 29.2%, and the total deformation maximum decreased by 18.1%. The area of the leakage hole bears on the cleanliness of the duck egg, the larger the area, the cleaner they were. This was because that duck dropping passed through the hole and fell onto the manure without sticking to the bottom wire mesh to soil the duck egg. Smaller deformation meant better structural stability. To test the feasibility of the optimization result, this research team experimented on cage-rearing laying duck using the bottom wire mesh optimized in a welfare duck farm of Hubei Shendan Healthy Food Company. The experiment included 384 ducks weighting in (1 350±50) g and lasted for a whole month. Ducks were divided into test group and control group living in the same environment. 2 ducks were raised in every cage. The results showed that the bottom wire mesh had a significant positive effect on duck egg cleanliness (P<0.01), and the average cleanliness of duck egg in the test group was 1.21 which was lower than 2.01 in the control group. It's known that cleanliness had negative correlation with effect. Before and after optimization, the bottom wire mesh had no significant effect on duck feather damage, laying rate and duck egg breakage rate. During the experiment, there was no obvious mass duck leg injuries in the experimental group, and the rate of death and elimination were in a reasonable interval in comparison with the average in the farm. This study solved the problem that the surface of duck egg shell was seriously polluted, and has high practical value. Meanwhile, this research method can provide reference for the development of furnished cage wire for poultry cage-rearing equipment.