Background: Lots of studies of acute ischemic stroke (AIS) had been conducted at low altitude regions, and related findings were used to instruct clinic management while corresponding studies at high altitude were few. This study aimed to analyse AIS clinic characteristics at high altitude regions by conducting a hospital-based comparative study between Tibet and Beijing. Methods: This study included the diagnoses of AIS patients from People’s Hospital of Tibet Autonomous Region (PHOTAR) and Peking University First Hospital (PUFH) between 1st January 2014, and 31st December 2017, where data including patient demographics, treatment time, onset season, risk factors, infarction location, laboratory data, image examination results, treatments, and AIS subtype were collected and compared. Continuous and categorical variables were analysed with a two-sample t-test or Wilcoxon rank sum test and chi-square test, respectively. Significant risk factors were examined with binary logistic regression analysis.Results: In total, 236 and 1021 inpatients from PHOTAR and PUFH were included, respectively. The PHOTAR patients were younger than the PUFH patients (PConclusion: In Tibet, the average age of AIS patients were less, and anterior circulation infarctions were also more common. Erythrocytosis and hyperhomocysteinemia may contribute to these differences. Here young adult stroke also accounted for a higher proportion, and this may be associated with erythrocytosis. Our findings present the first hospital-based comparative study in Tibet and may contribute to policies for stroke prevention in this region.