Objective The purpose of this study is to select suitable ages of rats for the CPR (cardiopulmonary resuscitation) animal model. The neurological function score and subgroups analysis are evaluated in 2 month old and 4 month old animal groups. Methods Based on the evaluation of physiological indexes including ECG, blood pressure and neurological function defect score (NDS) and subgroup analysis, the stability of CPR rats model was compared between 2 month old and 4 month old animal groups. Results The results showed that, the model rate of the ventricular fibrillation was induced by electrical stimulation, the 4 month old group was 87.5%, significantly higher than the 2 month old group, however, there was no significant difference between the two groups in the mortality rate; For the changes of blood pressure during the process of CA(cardiac arrest) induced by electrical stimulation, the 4 month old group was significantly lower than the 2 month old group (P< 0.01); for the NDS at each time point after CPR, there was no significant difference between the two groups; however, the NDS subgroup analysis at different time points showed that there were different degrees of differences between the two age groups (P< 0.05). Comparing with the 2 month old group, the 4 month old group had a stable process during the animal model preparation, had an obvious cerebral blood hypoperfusion phenomenon and aggravation of brain injury after CPR. Conclusion The 4 month old rats are more suitable for preparation of CPR animal mode, the model rate is high, the brain injury aggravate. It is more suitable evaluation for basic research and treatment of CPR.