〔Abstract〕Objective To investigate the effect of "three-step" treatment of fenestration decompression combined with twostage curettage and artificial bone powder implantation on clinical efficacy and cyst volume in patients with large cysts of the jaw. Methods A total of 46 patients with large cysts of the jaws who were admitted to Dongguan Donghua Hospital from September 2019 to November 2020 were selected. They were divided into to an bservation group and a control group according to the random number table method, with 23 cases in each group. The observation group was treated with fenestration decompression combined with two-stage curettage and artificial bone powder implantation, while the control group was treated with curettage of jaw cyst only. The clinical efficacy, related clinical indicators, postoperative pain degree, complication rate, recurrence rate, cyst volume and bone condition were compared between the two groups. Results The total effective rate of patients in the observation group was 95.65 %, which was higher than 73.91 % in the control group, and the difference was statistically significant (P < 0.05). The operation time and hospitalization time of the observation group were significantly shorter than those of the control group, and the amount intraoperative blood loss was significantly less than that of the control group, and the differences were statistically significant (P < 0.05). The visual analogue scale (VAS) scores of patients in the observation group at 2 h, 4 h, 6 h and 12 h after operation were significantly lower than those in the control group, and the differences were statistically significant (P < 0.05). The cyst cavity volume reduction, bone hyperplasia thickness and bone mineral density in the observation group were significantly higher than those in the control group, and the differences were statistically significant (P < 0.05). The incidence of complications in the observation group was 0.00 %, which was lower than 21.74 % in the control group, and the difference was statistically significant (P < 0.05). Six months after operation, the recurrence rate of the observation group was 0.00 %, which was lower than 17.39 % of the control group, and the difference was statistically significant (P < 0.05). Conclusion Fenestration decompression combined with two-stage curettage and implantation of artificial bone powder for the treatment of large cysts of the jaw has obvious therapeutic effect, which can improve clinical relevant indicators, reduce postoperative pain, and reduce the incidence of postoperative complications. It can also promote the reduction of cyst volume and increase the thickness and bone density of bone hyperplasia.