【Abstract】 Objective The aim of this study was to assess the risk factors associated with the severity of allergic rhinitis among rhinitis patients caused by cypress pollens. Methods Patients of seasonal allergic rhinitis with or without asthma caused by cypress pollens were recruited into the study conducted in the Allergy Department of Peking Union Medical College Hospital. The information about demographic characteristics and clinical features of the patients were collected through a questionnaire survey. During the cypress pollen season, patients recorded daily symptom scores in the electronic diary cards. Then the associations between the features of patients and their daily symptom scores were analyzed to investigate potential risk factors affecting the severity of allergic rhinitis. Results Multiple linear regression analysis showed significant positive correlation between the time length of outdoor exposure of the patient and his daily symptom score in the cypress pollen season, with regression coefficient of 0382, 95% CI (0163，0601). There was also significant correlation between positive family history of allergic diseases and higher daily symptom score, with regression coefficient of 0926, 95% CI (0188，1664). By contrast, no significant association was observed between the daily symptom score and duration of rhinitis, history of wheeze, exposure to furbearing pets, or tobacco exposure. Conclusion The severity of allergic rhinitis caused by pollens might be associated with the family history of allergic diseases and the time length of outdoor exposure during the pollen season.