Objective：To explore the differences between decompression and curettage on the treatment of mandibular odontogenic cyst. Methods：A total of 28 patients with mandibular odontogenic cyst over 3 teeth involvement in diameter（D≥6 cm）were selected and divided into the decompression group and the curettage group. The operation time and postoperative recovery were compared between the two groups. The preoperative and postoperative cone-beam CT（CBCT）data after 3，6，9 and 12 months were collected and reconstructed in three-dimension. The changes of bone volume fraction of the lesion and the newly regenerated bone were measured，while the relative position between cyst and the neural tube was also observed. Results：Mean operation time of the decompression group was significantly shorter than that of the curettage group（P < 0.05）. The class-A healing rate of the decompression group was significantly higher than that of the curettage group（P < 0.05）. The average cyst volume decreased more in the decompression group than in the curettage group in 3，6，9 and 12 months after the operation（P < 0.05）. The bone volume fraction of newly regenerated bone was significantly higher in the curettage group than the decompression group after 3 and 6 months（P < 0.05）. However，there was no significant difference after 9 months（P > 0.05）. It was significantly lower in the curettage group after 12 months（P < 0.05）. Ten cases with neurothlipsis preoperatively all had a recovery of neural tube in CT images after the decompression. Conclusion：Decompression can be a better choice for the treatment of mandibular odontogenic cyst.