Abstract: By using the computer simulation of the physical processes and the experiment, the influence on the image quality in different precisions was studied. The results indicated that the effects of the axial accuracy and the horizontal motion accuracy on the image reconstruction can be reduced or eliminated. The effects of the rotation accuracy and the repeatability varied with the accuracy and were unpredictable. And the effect related to the position and the density distribution of the test was changed with different angle and was hard to forecast.