Background and Aims Lymphatic leakage is a common complication after cervical lymph node dissection, for which the effects of traditional treatment methods are relatively limited. Pseudomonas aeruginosa injection for the treatment of wound surface can effectively promote the local inflammatory response and thereby closure of the leakage point. Therefore, this study was performed to effect of pseudomonas aeruginosa injection on drainage volume of patients with papillary thyroid carcinoma (PTC) with lymphatic leakage after cervical lymph node dissection as well as its safety, so as to clarify the application value of pseudomonas aeruginosa injection.Methods The data of 69 PTC patients with lymphatic leakage after cervical lymph node dissection treated in the Thyroid Surgery Department at the First Affiliated Hospital of Zhengzhou University between January 2019 and January 2020 were retrospectively analyzed. According to the treatment method for lymphatic leakage, the patients were divided into control group (37 cases, undergoing conventional bilateral tube placement for negative pressure drainage during surgery) and observation group (32 cases, receiving two pseudomonas aeruginosa injections through a drainage tube on postoperative day (POD) 4 and 6, based on the treatment of control group). The postoperative drainage volume and body temperature changes were compared between the two groups, and the drainage time and the incidence of adverse reactions were also recorded.Results There were no significant differences in the drainage volume between the two groups on POD 1, 2 and 3 (all P>0.05), and the drainage volumes on POD 4, 5 and 6 in observation group were significantly lower than those of control group [(310.79±32.16) mL vs. (338.64±34.55) mL, (157.82±16.43) mL vs. (325.43±33.96) mL, (87.34±8.59) mL vs. (333.68±34.59) mL, all P<0.05]. The body temperatures on POD 6 and 7 in observation group were significantly higher than those in control group [(37.78±3.77) ℃ vs. (35.96±3.60) ℃, (37.65±3.72) ℃ vs. (35.79±3.68) ℃, both P<0.05], but there was no significant difference in body temperature between the two groups at other time points (all P>0.05). The drainage time in observation group was significantly shorter than that in control group [(6.17±0.63) d vs. (7.28±0.75) d, P<0.01]. Adverse reactions such as local fever and chilling occurred in some cases in observation group within 2 weeks after surgery, and the body temperature returned to normal after physical cooling. The overall incidence of adverse reactions in the observation group was higher than that in the control group (12.50% vs. 8.11%), but the difference did not reach a statistical significance (P>0.05).Conclusion Pseudomonas aeruginosa injection is effective in the treatment of PTC patients with lymphatic leakage after cervical lymph node dissection. It can reduce the drainage volume and shorten the drainage time. Some patients may have increased body temperature and fever, which can be relieved after symptomatic treatment, and will not affect the treatment.