Objective To explore the correlation of heart rate variability(HRV)and cardiac output by PICCO with anesthetic depth by Narcotrend monitoring. Methods 60 patients with radical resection of esophageal cancer were enrolled in the study. PICCO was used to monitor ECG and Narcotrend was use to monitor anesthetic depth.The NT value,NT grade,Cardiac index(CI),heart rate(HR),mean arterial pressure(MAP),cardiac output(CO),Poincare scattergram Scatter plot minor axis(SD1)and scatter plot major axis(SD2)were recorded and measured at the time points of pre-anesthesia induction(T1),post-successful intubation(T2),tracheal intu-bation moment(T3),lung collapse for 30 min(T4),post-lung ventilation(T5)and 10min after operation(T6). Results Person's correlation analysis showed that during the monitoring period(T1-T6),CI,CO,SD1 and NT showed a low linear correlation(P < 0.001);SD2 was significantly correlated with NT(P <0.001). There was a low linear correlation between CI,CO,SD1,SD2 and NT at the operation time(T2-T5). Conclusion During general anesthesia,heart rate variability(SD1,SD2)and cardiac output(CO)are correlated with the NT value of anesthesia depth.Collaborative monitoring could help to enhance the safety of anesthesia.