To make space image stabilization system ensure the accuracy of the tip/tilt mirror and increase its support strength,a flexible support structure is designed using stress relief groove method,and a flexible connection between the mirror and its support is established using glue.The equivalent stiffness method is used to build fine finite element model for a planar-type layer.Meanwhile,equivalent stiffness matrix is deduced and calculated.The finite element model of tip/tilt mirror assembly is built,and then the modal analysis is done.The results show that the first resonance frequency is 704.24 Hz.Comparing with the 693.5 Hz of real experimental results,the error is only 1.5%.This shows that the stress relief groove method and glue layer’s finite element modeling method can complete the design and analysis of flexible tilt/tilt mirror effectively.Also it can provide a reference for similar optical projects in the flexible support design and analysis.