Objective To explore the changes and correlation between bone mineral density and migration ability of bone marrow mesenchymal stem cells (BMSCs) in patients with spinal tuberculosis. Methods From June 1, 2020 to December 1, 2021, 72 patients with spinal tuberculosis underwent spinal internal fixation (tuberculosis group) and 76 patients with thoracolumbar fracture or spinal stenosis underwent spinal internal fixation (control group) in a hospital were selected, bone mineral density of patients was determined, BMSCs were extracted from blood in screw path of 6 patients in tuberculosis group and control group respectively, the extracted BMSCs were cultured simply and co-cultured with BCG (BCG was added to BMSCs for co-culture), the migration rates of BMSCs at the 8th, 16th and 24th hours in each group was measured by scratch test, difference of migration ability of BMSCs in each group was compared, correlation between bone mineral density and migration rate of BMSCs was analyzed. Results Bone mineral density ([0.84±0.19] g/cm²) in tuberculosis group was lower than that in control group ([0.95±0.16] g/cm²), difference was significant (P < 0.05); migration rate of BMSCs in tuberculosis group was lower than that in control group (P < 0.05); after co-culture with BCG, the migration ability of BMSCs in tuberculosis group still significantly decreased (P < 0.05). The correlation coefficient (r value) between migration rate of BMSCs and vertebral bone mineral density at the 8th and 16th hours were 0.80 and 0.67 respectively. Conclusion Compared with patients with thoracolumbar fracture or spinal stenosis, bone mineral density of patients with spinal tuberculosis is significantly lower, migration ability of BMSCs of patients with spinal tuberculosis is weakened; BCG has no significant effect on the migration ability of BMSCs, and bone mineral density is positively correlated with migration rate of BMSCs.