The paper aims to optimize the wall thickness design of the incubator, study the optimal wall thickness of the incubator under the conditions of different ambient temperature and material thermal conductivity by characterizing the thermal insulation performance of the incubator. A finite element model was built; the experiments and finite element results were compared; and the reliability of the finite element model was verified by experiments. The thermal conductivity of the material in the model and the ambient temperature conditions were changed to study the influence of wall thickness on insulation performance of incubator. For incubator with a thermal conductivity of 0.01-0.075 W/(m•K) at the ambient temperature of 20-50 ℃, the wall thickness increased from 10mm to 35 mm; the thermal insulation performance changed greatly; when the wall thickness increased from 35 mm to 45 mm, and the thermal insulation performance changed slowly. Under the same ambient temperature condition, the increase of wall thickness was the same. The smaller the thermal conductivity was, the more significant the thermal insulation performance was. For incubators of the same thermal conductivity, the increase of wall thickness was the same. The lower the ambient temperature is, the more significant the thermal insulation performance increased. Under different ambient temperatures and thermal conductivity of materials, the optimal wall thickness of the incubator is 35-40 mm. It lays a theoretical foundation for the optimal design of the incubator.