Objective To research Chinese medicine syndrome classification of elderly primary lung cancer so as to provide reference for clinical treatment.Methods Chinese medicine syndrome information scale for elderly primary lung cancer was established according to relative literature in CNKI from the year 1979to 2009.Relevant data was collected as evidence factor in 303patients.Chinese medicine syndrome of elderly primary lung cancer was summarized by cluster analysis and principal component analysis.Results Chinese medicine syndrome of elderly primary lung cancer could be classified as four syndrome groups

i.e.spleen-kidney yang deficiency with phlegm-stasis binding together

lung yin deficiency with spleen qi deficiency

phlegm-heat brewing in the lung with qi stagnation blood stasis

and yin deficiency internal heat with inhibition of lung qi.Conclusion Cluster analysis and principal component analysis are useful in researching on Chinese medicine syndrome classification

but the conclusion also could be affected by the researcher.