The one month survival rate after out-of-hospital cardiac arrest (OHCA) in the paediatric population remains low. Improving survival in paediatric OHCA by enhancing the quality of cardiopulmonary resuscitation (CPR) is important. In this study, we aimed to analyse the factors associated with CPR quality by using a real-time feedback device. Participants were prospectively divided into 4 groups: paediatric research fellows, paediatric residents, medical students (clerks), and paediatric critical care nurses. Then, the participants were asked to perform 5 cycles of CPR on a paediatric simulation manikin without prompts from feedback devices, and to repeat another 5 cycles of CPR after education with the 2015 paediatric advanced life support guidelines. A total of 75 participants were evaluated. In the overall analysis, an improvement in the percentage of participants meeting the target compression rate was observed (from 49.82% to 71.23%, P < 0.001). The percentage of participants achieving the target compression depth improved from 73.77% to 85.63% (P = 0.005). Among the 4 groups, the residents showed the most significant improvement in both compression rate (from 48.41% to 86.57%, P < 0.001) and compression depth (from 63.50% to 95.57%, P < 0.001). Inappropriate rate was a more important factor resulting in inadequate CPR performance than inappropriate depth. An excessive compression rate was also a common problem. In conclusions, the real-time CPR feedback device may help clinical physicians and nurses in improving the quality of chest compression. Excessive CPR compression rate may be a major cause of inadequate CPR performance.