Objective To research Chinese medicine syndrome class ification 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 1979 to 2009.Releva nt data was collected as evidence factor in 303 patients.Chinese medicine syndr ome of elderly primary lung cancer was summarized by cluster analysis and princi pal component analysis.Results Chinese medicine syndro me of elderly primary lun g cancer could be classified as four syndrome groups

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

lung yin deficiency with spleen qi defic iency

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

and yin d eficiency 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.