Referring to the optical rounded reflector of spherical surface used in a space remote sensor, a kind of flexible structure was designed for regulating thermal deformation. Theoretical analysis was done to its dynamic model and parameter of structure, and simulating analysis was also done to reflector module with technology of the Computer Aided Engineering (CAE) in order to solve the status of high rigidity of structure and poor thermal stability of thermal dimension. With the regulation of flexible structure, the optical reflector should keep not only the high rigidity of structure under the environment of statics and dynamics, but also fine stability of thermal dimension under thermal environment. Analysis result indicates that the surface accuracy of reflector meets the needs of the imaging quality under mechanics and thermal load, and the value of PV is less than 63.2 nm, which shows that the flexible regulating structure is reasonable to actual structure of the space remote sensor.