Objective To analyze the characteristics of emergency observation patients who unplanned return to the rescue room，and explore its risk factors. Methods A retrospective analysis was conducted on 2 735 patients in emergency observation room who were transferred from the rescue room of a tertiary Grade-A general hospital from January 1，2019 to December 31，2021. The rate of unplanned return to the rescue room was statistically analyzed，and the differences of clinical characteristics between the group of unplanned return to the rescue room and the non-return group were compared. The risk factors of unplanned return to the rescue room were analyzed by binary logistic regression. Results A total of 87 patients returned to the rescue room unplanned，the rate of unplanned return was 3.2%. Logistic regression analysis showed that age（OR=1.021），unexplained abdominal pain （OR=2.916），and trauma（OR=0.226） was associated with the unplanned return to the rescue room（P<0.05）. Conclusion Age and unexplained abdominal pain are risk factors for unplanned return to the rescue room. It is suggested to establish a standardized evaluation process for patients who are transferred to the observation room， especially elderly patients and patients with unexplained abdominal pain，so as to predict the risk of condition changes and reduce the incidence of unplanned return to the rescue room.