The earth simulator as infrared earth sensor ground simulation test and calibration of the important equipment, because the cone scanning earth simulator existing cannot provide variable earth angle problem, the paper proposed a design scheme of variable earth angle conical scanning earth simulator, and the structure of the main part of the cold plate and hot plate was designed in detail. Although two pieces of cold plate are large and difficult to reach a rotation accuracy, they could be driven by an electric push through two connecting rod mechanisms, thus a threedimensional simulation model is established. Stress analysis on bracket could be done, as well as thermal analysis on cold and hot plate, by applying finite element software ANSYS. Experiments show that the structure design is reasonable, and it can meet the infrared earth sensor testing and calibration requirements.