By applying mechanics and space flight principle，aim at the strapdown optical seeker special characteristics，to set up the pitch and azimuth two axes platform optical seeker model of the flight system． Then we described the coordinate system of the line of sight in the space and its transformation

the stability of the centerline of seeker sensor beam in the vehicle body disturbance and the algorithms principle of navigation flight were studied．Check up the influence of vehicle aero elasticity to the seeker works. Based on this model，the computer simulation of the missile system flight is done，the result show that the image have a top dithering line of sight bias about 0.5°on the condition of vehicle aero elasticity disturbance

it is easy to lose the target and unable to track. If we can track the target on-time

when filtered the line of sight rate

the output of guidance single and the miss distance are almost consistent with and without the aero elasticity disturbance

and the miss distance approximately 1 meter.