Bone marrow toxicity is very common side effect during radio-chemotherapy treatment of pelvic tumors. In this study, six patients with cervical cancer were included. The Bone marrow fat faction of the subjects were evaluated using quantitative fat fraction MR technique before each week’s treatment and at the end of whole five weeks’ therapy. The results indicated that MRI was sensitive to marrow composition changes and can evaluate the real time bone marrow toxicity during radio-chemotherapy. This could potentially benefit patient with a more optimized treatment plan.