Abstract:〔Abstract〕 Objective To investigate the effect of esketamine on patient-controlled intravenous analgesia (PCIA) after low temperature plasma ablation of tonsil in children. Methods Sixty children who underwent low temperature plasma ablation of tonsil in Gongyi People's Hospital from January 2020 to June 2022 were selected and divided into a control group and an observation group by random number table method, with 30 cases in each group. The PCIA pump formula of the observation group was esketamine + Flurbiprofen ester + Palonosetron; The PCIA pump formula of the control group was Sufentanil + Flurbiprofen ester + Palonosetron. Clinical anesthesia related indexes, visual analogue scale (VAS) score, arterial oxygen saturation (SpO2) and adverse reactions were compared between the two groups. Results The proportion of crying children during anesthesia induction and children supplemented with propofol during recovery, Aono score and face legs activity crying consolability (FLACC) pain score in the observation group were lower than those in the control group, and the differences were statistically significant (P < 0.05). The VAS scores in the postoperative period in the observation group were lower than those in the control group, and the differences were statistically significant (P < 0.05). At 2 hours and 4 hours after operation, SpO2 in the observation group was higher than that in the control group, the difference was statistically significant (P < 0.05). There was no significant difference in SpO2 between the two groups at 12 hours and 24 hours after surgery (P > 0.05). There was no significant difference in the incidence of postoperative adverse reactions between the two groups (P > 0.05). Conclusion The application of esketamine after low temperature plasma ablation of tonsil in children has a good analgesic effect, and the short-term respiratory circulation ability is stable after surgery, and does not increase the occurrence of adverse reactions.