Objective To investigate the constituent ratio and clinical features of diffuse interstitial lung disease（DILD） in Chongqing city.Methods Data was collected from all patients diagnosed as DILD in five comprehensive teaching hospitals in Chongqing from 2002 to 2006.The disease constituent ratio of DILD in the respiratory department or in the whole hospital was analysised.Meanwhile the clinical manifestation and the laboratory examination such as lung function and biopsy were also analysised.Results Mean age of DILD patients is （61.65±13.31）years with a ratio male to female of 1.83.The constituent ratio of DILD were 2.83‰ in respiratory department and 0.30‰ in hospital in 2002，and increased to 8.29‰ and 0.48‰ respectively in 2006.Graticule（62.20%）and honeycombing（24.50%） were predominant imaging manifestations.47.55% patients had restrictive lung function impairment，and 51.05% had mixed lung function impairment.Pathologic examination revealed UIP as the most common type，however，81.82% cases could not be classified to any category pathologically.Conclusions The prevalence of DILD increased progressively from 2002 to 2006.A definite diagnosis of DILD demands cooperation of physicians，radiologists and pathologists.