Objective To assess the diagnostic value of ~(18)F-FDG PET/CT combining chest breath-hold spiral CT in preoperative primary tumor staging (T stage) of non-small lung cell cancer (NSCLC) before operation. Methods Ninety NSCLC patients underwent curative surgical resection after integrated ~(18)F-FDG PET/CT and chest breath-hold spiral CT examination. Two experienced radiologists blindedly staged all primary tumors in consensus by CT and PET/CT images. Surgical and histopathologic results served as the golden standard for determing the staging value of CT and PET/CT. T stage was assigned according to the seventh edition of TNM Classification of Malignant Tumors adopted by American Joint Committee on Cancer. Results According to pathological results, CT and PET/CT classified T stage accurately in 75.56% and 82.22%, respectively (P=0.03). CT and PET/CT accurately classified 3 and 6 patients respectively in 8 patients of central cancer with atelectasis, 2 and 4 metastases respectively in 5 patients at the ipsilateral lung. Conclusions Being able to describe the morphology, size and invasive region of primary tumor in NSCLC distinctly, CT is the main imaging method for T stage. ~(18)F-FDG PET/CT has unique value in differentiating center cancer with atelectasis and diagnosing pulmonary metastasis.