0bjective To investigate the relationships between the peripheral lung cancer and pulmonary vessels or bronchi by 16-row muhislice computed tomography(MSCT)and analyze the related factors.Methods Fifty-four patients with peripheral lung cancer confirmed pathologically underwent contrast-erdaanced MSC TI Multiplanar reformation(MPR)and maximum intensity projection(MIP)in all patients were used to demonstrate the relationships between the peripheral lung cancer and pulmonary vessels,bronchi.The relationships were categorized five types:Type 1,erupted at the edge of nodule. Type 2,erupted at the center of nodule.Type 3,penetrated through the nodule.Type 4,contacting the nodule but stretched or encased.Type 5,contacting the nodule but smoothly compressed.The pathology type,stage,size,density and location of the peripheral lung cancer were recorded and the relationships with five types were evaluated by using Chi-square test and correlation analysis.Results (1)Tumor-bronchi relationship:type 1(33,61.1%)was more often seen in≥2.0 cm and solid lesions with stage Ⅱ-Ⅳ.while Type 2(14,25.9%)was often seen in<2.0 am and part-solid or non-solid lesions with stage Ⅰ.(2)Tumor-PA relationship:Type 1 was more often seen in≥2.0 am and solid lesions with stage Ⅱ-Ⅳ.while Type 2 was often seen in part-solid or non-solid lesions with stage Ⅰ.(3)Tumor-PV relationship:type 4 was the most common type(29,53.7%).Type 2(13,24.1%)was more often seen in part-solid or non-solid lesions.(4)Tumor-bronchi relationship and tumor-PA relationship had a positive correlation(r=0.5265,P<0.01).Conclusions MSCT can demonstrate the relations between the peripheral lung cancer and bronchi.PA and PV.It is useful for the differential diagnosis and prognosis evaluation of the lung csncer.