In order to improve the accuracy of stereophotogrammetry,a computational model of motion blur is established for spaceborne TLA cameras. According to the reasons of motion blur,it is divided into two parts:the motion blur caused by flight velocity and attitude instability. The effect of flight velocity and attitude instability on motion blur at the camera exposure is studied by coordinate transformation. The motion blur caused by pitching,rolling and yawing is mathematically modeled. The experimental results show the conclusions as follows:(1) motion blur of spaceborne TLA cameras is variant in space,pitching and rolling have more effect on motion blur of TLA cameras than yawing;(2) for nadir-looking sensor,the motion blur caused by yawing is ignored,but for forward-looking and backward-looking sensors,it can′t be ignored because it introduces space variant to the motion blur distribution on the CCD arrays;(3) the motion blur caused by attitude instability is smaller to the nadir-looking sensor than the forward-looking and backward-looking sensors.