Objective To investigate the safety and efficacy of different doses of tranexamic acid (TXA) in posterior cervical laminectomy with lateral mass screw fixation and bone graft fusion by a prospective clinical study. Methods The middle-aged and elderly patients with cervical spondylotic myelopathy, who were admitted between January 2020 and January 2022 and scheduled to undergo posterior cervical laminectomy with lateral mass screw fixation and bone graft fusion, were studied as the research subjects. Among them, 165 patients met the selection criteria and were included in the study. The patients were allocated into 3 groups (n=55) by random double-blind lottery. Groups A and B were given intravenous infusion of TXA at 30 minutes before operation according to the standards of 15 and 30 mg/kg, respectively; and group C was given normal saline in the same way. There was no significant difference in gender, age, body mass index, and preoperative D-dimer, hemoglobin (Hb), and hematocrit (HCT) between groups (P>0.05). The intraoperative bleeding, intraoperative blood transfusion, postoperative drainage volume, drainage days, and postoperative hospital stay were recorded. The Hb, HCT, and D-dimer were compared before operation and at 3 days after operation. Venous ultrasonography of the lower extremities was taken after operation to assess thrombosis; and the postoperative hematoma and epilepsy were also observed. Results All operations were successfully completed, and the incisions healed by first intention. The differences in intraoperative bleeding volume, postoperative drainage volume, drainage days, and postoperative hospital stay between groups were significant (P<0.05). The above indexes were significantly less in group B than in groups A and C. During operation, 14 patients in group A and 23 patients in group C were transfused, and no patient in group B had blood transfusions. Compared with groups A and C, the blood transfusion volume in group B significantly decreased (P<0.05), and the difference between groups A and C was not significant (P>0.05). There was no significant difference in the differences of D-dimer, Hb, and HCT before and after operation between groups (P>0.05). At 5 days after operation, the venous ultrasonography of the lower extremities showed that the 2 cases of intermuscular venous thrombosis occurred in groups A, B, and C, respectively. No hematoma or epilepsy occurred after operation. Conclusion The application of 15 and 30 mg/kg TXA in posterior cervical laminectomy with lateral mass screw fixation and bone graft fusion can reduce intraoperative bleeding and postoperative drainage volume, postoperative drainage days, and postoperative hospital stay. And application of 30 mg/kg TXA can reduce intraoperative blood transfusion, without increasing the risk of lower extremity venous thrombosis, hematoma, and epilepsy.