AIM: To compare the effect of different courses of budesonide nasal spray on the postoperative efficacy of endoscopic dacryocystorhinostomy.METHOD: Prospective study. A total of 90 patients(90 eyes)with chronic dacryocystitis who underwent endoscopic dacryocystorhinostomy in our hospital from January 2019 to April 2022 were selected, and they were randomly divided into three groups. In group A, 30 patients(30 eyes)continued to use budesonide nasal spray for 2mo after surgery; in group B, 30 patients(30 eyes)continued to use budesonide nasal spray for 3mo after surgery; in group C, 30 patients(30 eyes)continued to use budesonide nasal spray for 4mo after surgery. Follow-up for 6mo after surgery, Lund-Kenndey score, surgical efficacy and complications of the three groups were compared.RESULT: At 3, 4 and 6mo after surgery, the Lund-Kenndey score of group C was lower than that of group A(P<0.05), and there was no statistical difference between group C and group B(P>0.05). Following up to 6mo, the surgical efficacy of group C was better than that of group A, and the incidence of complications was lower than that of group A(P<0.05); There was no statistically significant difference in efficacy and complications between group C and group B(P>0.05).CONCLUSION: Budesonide combined with endoscopic dacryocystorhinostomy has acceptable efficacy in the treatment of chronic dacryocystitis. After 3mo of treatment, inflammation can be well controlled, which can reduce the occurrence of postoperative complications and improve the effective rate of surgery. However, increasing the treatment course cannot further improve the effective rate of surgery.