To investigate the relationship between chronic blepharitis and evaporative loss dry eye.Forty-one patients (82 eyes) were diagnosed as chronic blepharitis from November 2002 to April 2003 in Beijing Tongren Eye Center, of which 22 cases were male and 19 female. All patients' ocular surface was judged by Schirmer I test, tear film break up time (BUT) and Tearscope. Meibomian gland secretion was used for bacteria culture and antibiotic sensitivity test. Thirty patients (60 eyes) of glaucoma, cataract and LASIK before surgery were used as control, which included 16 male and 14 female. Microbiological results of meibomian gland secretion were compared and the statistical difference was evaluated by chi(2) test.Of the blepharitis group, ST value was less than 10 mm in 30 eyes (36.6%), BUT less than 10 s in 56 eyes (68.3%) and tear film tearscope evaluation more than 3 grade in 46 eyes (56.1%). The bacteria spectrum of meibomian secretion in both groups was similar, which included staphylococcus epidermidis, staphylococcus aureus and corynebacterium. However, the bacterium culture positive rate and antibiotic sensitivity showed significant difference (P < 0.05).The chronic blepharitis is one of important cause in evaporative loss dry eyes.