Aims:To explore the rule of N2 disease based on the lobar location of lung squamous cell carcinoma.Methods:A retrospective review of CT and clinical data of 438 patients with lung squamous cell carcinoma had been studied.To statistic the rate of N2 disease of different lobar location of lung squamous cell carcinoma.Results:The incidence and location of N2 disease of the 438 patients based on the location of the primary squamocellular carcinoma was as follows:for right upper lobe cancers,25% had N2 disease,most commonly in the 4R(36%) ;16% cases of right middle lobe had N2 and most commonly in the 4R(50%) and the 7th station(50%) ;30% cases of right lower lobe mass had N2 diseases and,most commonly in the 4R(31%) and the7th station(34%) ;left upper lobe,had 21% N2,most commonly in the 6th station(50%) ;and left lower lobe,24%,most commonly in the 7th station(43%) .Skip metastases(no N1,but N2) was appeared at left upper lobe lesions only.Patients with right-sided cancers have the similar incidence to have N2 disease(71/271,26%) as comparing with patients who had left-sided lesions(36/167,22%) (P>0.05) .Incidence of N2 diseases in right low lobe was more higher than other lobe,but have no significant difference compared to that of right upper lobe and left low lobe(P>0.05) .Incidence of N2 diseases in right middle lobe was the lowest when compared to that of other lobe(P<0.05) .Conclusion:There is a distinct predilection for the location of N2 disease based on the lobar location of primary lung squamous cell cancer.The location of lymph nodes metastasis had important rule in the classification and surgical dissection of lung squamous cell carcinoma. Aims: To explore the rule of N2 disease based on the lobar location of lung squamous cell carcinoma. Methods: A retrospective review of CT and clinical data of 438 patients with lung squamous cell carcinoma had been studied. To statistic the rate of N2 disease of different lobar location of lung squamous cell carcinoma. Results: The incidence and location of N2 disease of the 438 patients based on the location of the primary squamocellular carcinoma was as follows: for right upper lobe cancers, 25% had N2 disease, most commonly in the 4R (36%); 16% cases of the right middle lobe had N2 and most commonly in the 4R (50%) and the 7th station (50%); 30% cases of the lower lobe mass had N2 diseases and, most commonly in the 4R (31%) and the 7th station (34%); left upper lobe, had 21% N2, most commonly in the 6th station (50%); and left lower lobe, 24% most in the 7th station 43%) .Skip metastases (no N1, but N2) was was at left upper lobe lesions only. Patients with right-sided cancers have the the simila r incidence to N2 disease (71 / 271,26%) as comparing with patients who had left-sided lesions (36 / 167,22%) (P> 0.05) .Inidence of N2 diseases in right low lobe was more than than other lobe, but have no significant difference compared to that of right upper lobe and left low lobe (P> 0.05) .Incidence of N2 diseases in right middle lobe was the lowest when compared to that of other lobe (P <0.05) .Conclusion : There is a distinct predilection for the location of N2 disease based on the lobar location of primary lung squamous cell cancer. The location of lymph nodes metastasis had important rule in the classification and surgical dissection of lung squamous cell carcinoma.