Objective To understand the characteristics of dehydration instroke inpatients, and to explore the correlations among these characteristics, in order to provide a reference for developing measures to prevent dehydration.Methods According to basic principles of data mining, totally 11 559 records of 351 ischemic stroke patients with dehydration in neurological intensive care unit were collected.The Apriori algorithm was conducted to mine association rules of dehydration.Results A total of 279 strong association rules were obtained, and 9 strong association rules with clinical practical significance were obtained via analysis with professional knowledge.Characteristics of stroke patients with dehydration included severely dependent on self-care ability, indwelling gastric tube, disturbance of consciousness, and the correlation factors among these characteristics were NIHSS severe stroke symptom, aged 65 years or older, history of diabetes and hypertension, fever, using ventilator and diuretic, etc.Conclusion The ischemic stroke patients with dehydration are characterized with certain manifestations, so nurses can identify high risk population and factors of dehydration at an early stage according to strong association rules, and take preventive measures in time.