Objective To study the distributive law of TCM syndromes of lung cancer patients accompanied with hydrothorax.Methods For the 150 lung cancer patients accompanied with hydrothorax

recorded clinical symptoms and signs（including tongue and pulse）and the related inspections

and diagnosed with TCM syndrome differentiation according to the research design for determining their syndromes.The syndrome characteristics of the patients were discussed on the basis of judgment standard in order to find out the distributive law of TCM syndromes.Results The TCM syndromes of lung cancer patients accompanied with hydrothorax were mainly of 7 types:deficiency of both qi and yin

qi deficiency with phlegm-damp

qi deficiency with blood stasis

qi deficiency

phlegm-heat

qi stagnation

and qi stagnation with blood stasis.The different pathological types

clinical stages

and hydrothorax quantity of patients were without statistical significance in the distribution of TCM syndromes（P>0.05）.Conclusion The distribution of TCM syndromes of lung cancer patients with hydrothorax is complicated with pathological changes of both xu-deficiency and shi-excess

especially with qi deficiency as the main manifestation.There is no significant relation between the TCM syndromes and hydrothorax quantity

clinical stages

and pathological types of the patients.