Objective To analyze the first aid situation of patients with out-of-hospital cardiac arrest (OHCA) in Zhengzhou City, and to explore the related factors affecting the prognosis of cardiopulmonary resuscitation (CPR) in patients with OHCA. Methods Retrospective analysis of patients with OHCA admitted to Zhengzhou Emergency Medical Rescue Center from June 2016 to June 2018 was performed. General information of patients, such as gender, age, bystander, the quality of bystander CPR (medical personnel, non-medical personnel), 120 reception time (day/night), location (family, public place, hotel, other), emergency medical service (EMS) response time, duration of CPR, first detected heart rhythm, defibrillation, mode of ventilation (balloon mask, laryngeal mask, endotracheal intubation), epinephrine dose, cause of cardiac arrest, outcome of resuscitation [restoration of spontaneous circulation (ROSC) or death] were collected. The risk factors of CPR prognosis were analyzed with univariate and multivariate Logistic regression analysis. Results ① The result of general investigation: 7 728 cases with OHCA in the past two years, among whom 3 891 were clinically dead upon arrival, 1 413 were not rescued, 2 424 were actively rescued, and only 51 got ROSC. There were 73.71% (5 696/7 728) patients calling "120" during 07:01-23:00 and 26.29% (2 032/7 728) patients during 23:01-07:00. The response time of EMS was (9.36±6.75) minutes. Cardiac arrest mostly occurred at home, which accounting for 61.61% (4 761/7 728), followed by public places, which accounting for 16.19% (1 251/7 728). The incidence of cardiac arrest was higher in males than in females [63.11% (4 877/7 728) vs. 36.89% (2 851/7 728)]. 54.94% (4 246/7 728) of patients were over 60 years old. Cardiogenic factors were the most important etiology, which accounting 38.63% (2 985/7 728), followed by trauma, which accounting 19.16% (1 481/7 728). ② The risk factors of prognosis of CPR: univariate Logistic regression analysis showed that age, bystander CPR, 120 reception time, duration of CPR, first detected heart rhythm, epinephrine dose and the cause of cardiac arrest were related to the ROSC in OHCA patients [age: odds ratio (OR) = 0.450, 95% confidence interval (95%CI) = 0.257-0.787; bystander CPR: OR = 6.446, 95%CI = 4.695-8.851; 120 reception time: OR = 1.941, 95%CI = 1.114-3.382; duration of CPR: OR = 0.163, 95%CI =0.074-0.360; first detected heart rhythm: OR = 0.080, 95%CI = 0.042-0.155; epinephrine dose: OR = 0.423, 95%CI =0.241-0.740; cause of cardiac arrest: OR = 1.901, 95%CI = 1.091-3.314; all P < 0.05]. Multivariate Logistic regression analysis showed that non-medical personnel, medical personnel, shockable rhythm, duration of CPR < 10 minutes and epinephrine dose < 5 mg were favorable factors for ROSC in OHCA patients (non-medical personnel: OR = 24.552, 95%CI = 10.192-59.144; medical personnel: OR = 36.960, 95%CI = 17.572-77.740; shockable rhythm: OR = 0.036, 95%CI = 0.015-0.087; duration of CPR < 10 minutes: OR = 0.191, 95%CI = 0.069-0.526; epinephrine dose < 5 mg:OR = 0.259, 95%CI = 0.125-0.537; all P < 0.01). Conclusions ① Male patients with OHCA in Zhengzhou City were more than female patients, and the age of most patients was older than 60 years old. OHCA often happened at home, followed by public places. The etiology was mainly cardiogenic, followed by trauma. EMS response time was a little long, the success rate of recovery was low, and pre-hospital emergency treatment needs to be further improved. ② Bystander CPR, shockable rhythm, duration of CPR < 10 minutes and epinephrine dose < 5 mg were beneficial to ROSC.