Abstract: For some rigid targets of radar, such as aircrafts and ships, they hold the properties of geometry invariance during the motions. With this constraint, the 1-D range histories of the scatterers extracted from the radar echo signals can be applied to reconstruct the 3-D shape and the motion of the target. Considering to the poor robustness of the existing radar 3-D reconstruction algorithm based on geometry invariance, the motion inertia of the radar target is utilized in this paper to fit the motion path and via which the 3-D coordinates of the scatterers of the target are reconstructed optimally. Furthermore, the reconstruction error models are analyzed in this paper and the models of affine perturbation and Euclid reconstruction error are proposed. The simulation experiments verify that, after the affine matched correction, the fitted motion path is basically consistent with the real path so that the target’s motion features can be obtained efficiently. Meanwhile, the Euclid reconstruction error can be suppressed effectively with the optimal reconstruction proposed in this paper implemented and, as a result, the accuracy of the reconstruction can be improved.