Background: Cardiopulmonary resuscitation (CPR) plays an essential role in the treatment of sudden cardiac arrest (SCA), we aimed to evaluate the influencing factors on the effects of CPR in patients with SCA, to provide insights into the management of SCA.Methods: Patients who underwent CPR in the emergency department of our hospital from January 1, 2019 to June 30, 2021 were selected. We collected and analyzed the clinical characteristics of CPR patients. Logistic regression analyses were conducted to identify the risk factors of CPR failure.Results: A total of 308 CPR patients were included, the incidence of CPR success was 35.71%. There were significant differences in the age, time to the start of CPR, the type of heart rhythm in the first monitoring, duration of CPR and cumulative adrenaline dosage between CPR success and failure group (all P<0.05). No significant differences in the gender, cause of cardiac arrest and ventilation methods were found (all P>0.05). Logistic regression analyses indicated that age≥65y(OR2.132, 95CI%1.127~4.334), time to the start of CPR≥12min(OR2.503, 95CI%1.015~3.583), unable to defibrillation(OR1.856, 95CI%1.107~3.031), duration of CPR≥40min(OR2.162, 95CI%1.242~4.178), cumulative adrenaline dosage≥6mg(OR1.627, 95CI%1.151~2.472) were the independent risk factors of CPR failure(all P<0.05).Conclusions: The success and failure of CPR are affected by many factors. Early and effective interventions should be taken for these influencing factors in clinical practice. Due to the limitation of sample size, future large-sample and multi-center studies need to further explore the relevant influencing factors of CPR.