Objective：To compare the effects of lamina replantation after unilateral laminectomy operational on the prognosis of patients with intraspinal tumors，and to establish nomogram models for prediction of prognosis. Method：The clinical data of 220 patients with intraspinal tumors treated by unilateral laminectomy were collected and retrospectively analyzed. The patients were divided into experimental group and control group according to whether the isolated bone was reset in situ or not. Operation time，intraoperative blood loss，complications after operation，neurological function of spinal cord and spinal stability were compared. Generalized additive model was used to establish prediction models for prognosis of patients by fitting the relationship between the outcome variables and baseline indicators. Results：One year after operation，the improvement rate of spinal cord function and clinical symptoms in the experimental group was better than those in the control group（P=0.008 and P < 0.001）. Patients receiving a lower cervical laminectomy or a single segment laminectomy suffered more blood loss if conducting a lamina reposition（P=0.027 and P=0.001），while patients underwent a thoracic laminectomy or double segments laminectomy showed less blood loss when a lamina reposition conducted（P=0.003 and P < 0.001）. The prediction models of McCormick score < 3，improvement of McCormick score，and spinal deformation in one year after operation were established. The specificity，sensitivity and accuracy of the models were 0.921，0.838 and 0.546，0.526，0.576 and 0.906，0.870，0.836 and 0.798，respectively. Conclusion：Lamina reposition after unilateral laminectomy for intraspinal tumors helps to improve spinal cord function and reduce complications. Lamina reposition is not recommended when operational exposure happens on a single segment vertebra or in the lower cervical lamina，but recommended when unilateral laminectomy happens on two segments vertebra or cervical vertebra.