Objective: In order to improve the success rate of resuscitation, this thesis did a retrospective observational study of all individuals who suffered from ventricular arrhythmias out-of-hospital and accepted Shanghai medical emergency center rescue between 2013 and 2015 in Shanghai. Methods: A total of 71 cases of shockable ventricular arrhythmias who accepted Shanghai medical emergency center rescue between 2013 and 2015 were included. Data recorded included patient demographics, alert time, availability of witnesses CPR, response time, scene time, time to hospital arrival, time to recovery of spontaneous circulation, initial resuscitation success rates, and finally, rates of successful discharge from hospital. Statistical analysis was performed to find the related factors of successful resuscitation. Results: The incidence of shockable ventricular arrhythmia was significantly higher in males (71.8%) than in females, and it was more likely to be found during daytime (63.38%) than at night. In Shanghai, witnesses CPR rate was only 25.35%, but showed a rising trend (P>0.05). We observed an increase in rates of successful discharge from hospital from 28% to 46%. This increase was observed whilst many other factors including response times site times and transport times remained relatively unchanged (P>0.05). The survival to hospital discharged was related with return of spontaneous circulation time (P<0.05). Conclusion: The rate of successful discharge from hospital of out-of-hospital shockable ventricular arrhythmia increased year by year during 2013 to 2015, and was related with recovery of spontaneous circulation time. In our country, it is an important measure to improve the success rate by popularizing CPR and reducing the response time.