A serum method for evaluating therapeutic efficacy of acute leukemia has been built by magnetic beads-based biological mass spectrometric technology. After analysis of quality control sample, the reproduci-)bility) of within-run assay and between-run assay was obtained and consistent with the previous reports. This result) manifested that the method used for serum peptides analysis was stable and reliable. Serum samples from 30 patients with primary acute leukemia and those with complete remission after treatment were extracted by metal-chelated magnetic beads and detected by MALDI-TOF-MS. Peaks at the m/z range 1000-10000 were analyzed by FlexAnalysis 2.4 software and Biosun_MS software. Approximately 27 differential peaks that were of statistical significance(p<0.05) were obtained. Ten peaks were up-regulated) and 17 peaks were down-regulated) after complete remission, respectively. The diagnostic model based on these differential peaks achieved) 100% sensitivity and 90% specificity. The results indicated that the model based on magnetic beads extraction and MALDI-TOF-MS detection acquires high sensitivity and specificity. Further sequence identification of differential) peaks is useful for evaluation of therapeutic efficacy and mechanism research on acute leukemia.)