To analyze the distribution characteristics of traditional Chinese medicine(TCM) syndromes of pulmonary nodules(PNs) in Beijing.Methods:The medical data of four examinations in TCM of 271 PNs patients from Beijing were collected.The characteristics of TCM syndrome elements of PNs were determined by principal component analysis(PCA) combined with the criteria of syndrome elements.Subsequently,hierarchical cluster analysis was used to explore the TCM syndrome distribution characteristics of PNs in Beijing.Results:The syndrome elements of PNs were mainly phlegm turbidity,phlegm dampness,qi deficiency,blood stasis,and yang qi deficiency.The results of cluster analysis showed that the TCM syndromes of PNs were predominated by lung qi deficiency(34.3%),followed by lung qi and yin deficiency(19.2%),blood stasis obstructing collaterals(17.7%),phlegm-heat stagnation in the lung(16.2%),and liver stagnation and qi stagnation(12.5%).Conclusion:PNs are mainly in the lung,and are asthenia in origin and sthenia in superficiality and deficiency-excess in complexity.They can be clinically classified as lung qi deficiency,phlegm-heat stagnation in the lung,lung qi and yin deficiency,liver depression and qi stagnation,and blood stasis obstructing collaterals.The proportions of lung qi deficiency syndrome and lung qi and yin deficiency syndrome are high.In the treatment and syndrome differentiation,the deficiency of both qi and yin should be highlighted,and the treatment methods of tonifying qi and nourishing yin,strengthening lung qi,and moistening lung vessels should be applied,so that qi and blood can be regulated and smoothly flowed,and pathogenic factors cannot be accumulated.