3D ceramic substrate package is widely used in UV LED and power LED because of its good air tightness. We called the package of LED in 3D ceramic substrate package as 3D ceramic substrate LED package. However, there are many types of ceramic materials, and the thermal conductivity of these materials vary widely. In addition, there is little research on the optical performance of LED, which the dam related to. These limit the application of LED in 3D ceramic substrate package.In this paper, a thermal model of the 3D ceramic substrate LED package is established using finite element simulation and experimental verification. Moreover, TracePro was used to build the optical model of the 3D ceramic substrate LED package. The results show that the established thermal model matches the reality. The shape of the dam has little effect on the heat dissipation of the package. Reducing the chip operating temperature of the 3D ceramic substrate LED package lies in increasing the heat dissipation area and using a ceramic substrate with high thermal conductivity. The material and structure of the dam have a great influence on the optical performance. The total light emission intensity of package with circular dam is higher than that with the square dam, while the maximum light emission intensity of package with the square dam is higher than that with the circle dam.