Objective To investigate the correlation and consistency of electric impedance (ICON) and echocardiography (ECHO) in monitoring the heart function of pediatric critically ill patients. Methods A total of 53 children treated in the intensive care unit from January 2020 to March 2021 were recruited. ECHO and ICON were used to monitor cardiac function, and stroke volume (SV) and cardiac output (CO) were recorded to compare the correlation and consistency between the two methods. Results A total of 53 children (37 boys and 16 girls) were included, with a median age of 15.0 (5.1-63.0) months. There was no statistically significant difference in SV and CO measured by ICON and ECHO (P>0.05), and there was a significantly positive correlation (r=0.91 and 0.85, both P<0.001). The consistency of SV and CO monitored by ICON and ECHO was good, and the intra- class correlation coefficients (ICC) were 0.89 and 0.87, respectively (P<0.001). Bland-altman method was used for consistency analysis. The average SV difference between ECHO and ICON was 2.29 mL, and the consistency interval was -17.02-21.60 mL. The average difference of CO monitored by ECHO and ICON was 0.27mL, and the consistency interval was -1.83-2.36mL. Under the condition of using ventilator, the correlation coefficients of SV and CO measured by the two methods were 0.88 and 0.82 (both P<0.001), and the ICC values were 0.86 and 0.87 (both P<0.001). The correlation coefficients of SV and CO measured by the two methods without using the ventilator were 0.89 and 0.89 (both P<0.001), and the ICC valueswere 0.91 and 0.86 (both P<0.001). Conclusions ICON and ECHO have good consistency and correlation in monitoring the cardiac function of critically ill children, and are not affected by the use of ventilators. Therefore, they have certain application values in pediatric intensive care.