Objective To observe the functional changes of T lymphocytes in the spleen of rats with bone cancer pain.Methods forty-one healthy female Sprague-Dawley rats were used in this study, and were divided into blank control, PBS and Walker-256 tumor groups. Bone cancer pain model was established by inoculation of Walker 256 cancer cells into the tibial cavity. The paw withdrawal threshold (PWT), paw withdrawal thermal latency (PWL), and spontaneous pain(SP) were all measured before modelling (as base) and at 4, 6, 8, 10, 12, 14, 16, 18, and 20 days after modelling.The function of T lymphocyte proliferation, and the content of T lymphocytes and their subgroups in the spleen were detected by cell counting kit-8 method and flow cytometry, respectively, on day 20 after modelling.Results Before modellng, there were no differences of PWT, PWL, and SP between the PBS and model groups. After modelling, the PWT and SP of model group were significantly decreased on day 4, and were always lower than that of PBS group during the experiment. Statistical analysis revealed that Walker-256 cancer cell inoculation in the tibia induced a significant decrease in PWL on day 8, 10 and 12 after modellng. Compared with the control group, T lymphocyte proliferation, content of T lymphocyte (CD3) and subgroups (CD4 and CD8) in the PBS group were not significantly decreased. However, T lymphocyte proliferation and the content of CD3 lymphocytes in the model group were significantly lower than those in the blank control group and/or PBS group.Conclusions The bone cancer pain rat model may appear obvious mechanical allodynia and spontaneous pain. Its thermal pain hyperalgesiaonly occurred in the intermediate stage of bone cancer pain. The content of T lymphocytes and its subgroups, and the function of T lymphocyte proliferation are weakened to some extent in the bone cancer pain rat model.