High-accuracy beam scanning,pointing and tracing are the key points in the precision measurement and control fields.A light weight tip/tilt mirror which is made from material of SiC has been designed.The theory and analysis method of shock response spectrum in finite element analysis is introduced using large mass method.In the specify environment,a finite element model of the tip/tilt mirror is build in PATRAN and its shock response spectrum analysis is performed by NASTRAN.Model participation factors are figured out.The maximum response of displacement,acceleration and stress in the shock response spectrum analysis are calculated.The results of calculation show that the tip/tilt mirror meets the requirement of environment.It is useful for the design and development of the tip/tilt mirror.