Objective To explore the relevant influencing factors for restoration of spontaneous circulation (ROSC) in elderly patients with unexpected in-hospital cardiac arrest, and to provide references for preventing in-hospital cardiac arrest in elderly patients and improving the success rate of rescue. Methods A retrospective analysis method was adopted. The clinical data of 134 consecutive elderly patients with unexpected in-hospital cardiac arrest were collected. According to the outcomes after rescue, the patients were divided into the restoration of spontaneous circulation group （the ROSC group） and the non-restoration of spontaneous circulation group （the non-ROSC group）. Multivariate logistic regression analysis was performed to explore the influencing factors. Results Among the 134 patients, 69 patients had ROSC, with a success rate of 51.5%. Logistic regression analysis showed that age, rescue location, duration of continuous CPR, and cumulative dosage of adrenaline were the influencing factors for ROSC in elderly patients with unexpected in-hospital cardiac arrest （all P<0.05）. Conclusion The success rate of ROSC in elderly patients with unanticipated in-hospital cardiac arrest is relatively low. It is recommended that critically ill elderly patients be admitted to the ICU, and emergency instruments, equipment and drugs should be prepared in advance. After a sudden cardiac arrest in a general ward patient, the rapid response system should be immediately activated to improve the success rate of ROSC in elderly patients.