Objective To explore the diagnesticvalue of the inhalant allergens in patients with allergic disea-ses. Methods The intradermal tests(IT) of 20 types of the inhalant allergens which were supplied by Diagnosis Rea-gent Factory of Beijing Union Hospital were made on 1434 cases with allergic diseases. The samples were divided into two age groups:4～18 year-old(children group,n=318) and 19-80 year-old( adults group,n=1116). Distribution of the inhalant allergens of the two groups was investigated. Results A total of 1434 cases (male :702, female:732) were diagnosed with allergic diseases. There were 8 kinds of allergic diseases. The number of allergic rhinitis was the first place( 1130 cases,78.80% ). The first 9 positive allergens separately were: polyvalent pollen Ⅰ (51.05%),house dust(48.81% ) ,mixed inhalant allergens( 48.61% ), artemisia pollen( 46.86% ), dust mite( 45.19% ) , poly-valent insects(36.82% ) ,spring poLlen Ⅰ(33.99% ) ,ragweed pollen(31.24% ) ,spring pollen Ⅱ (30.68% ). There were 1289 cases(89.89% ) at ]east one type positively on allergens. The 19～40 aged patients were the most in dif-ferent age groups. The difference of positive detection rate of allergens was significant in different quarters ( P<0.01 ). Conclusion The youth and middle aged is easoer to suffer loom allergic diseases. Allergic rhinitis was the most common disease,and polyvalent pollen Ⅰ ,house dust,artemisia pollen,dust mite,ragweed pollen were the main allergens.