Abstract: Spatial resolution is the two most important parameters of CT image quality, and the test work of this parameter is main part of CT scanner's quality assurance. This paper represents two methods, which were dedicated for the assessment of spatial resolution in CT system, and analysis spatial resolution of CT system by using software tools. The comparative study of the two methods was carried out in 3 ICT systems under the same experiment condition. We found that the test result of disc phantom method is significantly higher than the result of practical-MTF method, and then the relationship between the test results of the two methods was discussed.