Objective:To investigate the effects of intraoperative irrigation with hypothermic 3% sodium chloride solution on surgery effect and post-tonsillectomy pain in adults.Methods:A total of 120 adult patients with the plasma tonsillectomy from January to December 2020 in the First Affiliated Hospital of Soochow University were divided into observation group A, observation group B, observation group C and control group according to random number table method, with 30 cases in each group. During operation, observation group A used hypothermia 3% sodium chloride, observation group B used room temperature 3% sodium chloride, observation group C used hypothermia 0.9% sodium chloride, control group used room temperature 0.9% sodium chloride. The quality of surgical field quality, operation time, blood loss in operation, duration of catheter, the postoperative wound pain at 24, 48, 72 h after operation were compared among four groups.Results:The surgical field quality scores were (2.07 ± 0.87) points in the observation group A, significantly lower than in the observation group B (2.57 ± 0.73) points, observation group C (2.60 ± 0.56) points and control group (3.10 ± 0.66) points, the differences were statistically significant ( t=2.71, 2.89, 5.61, all P<0.01). Amounts of blood loss in operation were (9.13 ± 1.74), (10.03 ± 2.81), (10.50 ± 2.09) ml in the observation group A, observation group B and observation group C, significantly lower than in the control group (15.23 ± 3.64) ml, the differences were statistically significant ( t=8.85, 7.54, 6.87, all P<0.01). At 24 h after operation, the scores of Numerical Rating Scale(NRS) were (3.23 ± 0.77), (3.53 ± 0.63), (3.80 ± 0.89) points in the observation group A, observation group B and observation group C, significantly lower than in the control group (4.43 ± 1.17) points. At 48 h after operation, the scores of NRS were (2.37 ± 0.72) points in the observation group A, significantly lower than in the control group (2.93 ± 0.83) points, the differences were statistically significant ( t values were 2.77-5.25, all P<0.01).There was no significant difference in operation time, duration of catheter and wound pain 72 hours after operation among the four groups ( P>0.05). Conclusions:Intraoperative use of hypothermic 3% sodium chloride solution can reduce the amount of blood loss in operation in adult patients with plasma tonsillectomy, increase the clarity of visual field, and effectively reduce postoperative pain.