Objective To explore the targeting distribution of FM HAS MTX in brain under magnetic field and magnetic targeting chemotherapy for malignant brain tumor.Methods FM HAS MTX carriers were injected into systemic circulation of 30 SD rats through caudal vein.A magnetic field was located at the right brain.MTX distribution in brain was observed at different time points(10,30,45 min),and MTX contents of left and right brains were compared at the the same time points.Meanwhile,the changes in MTX contents in brain were studied in the presence or absence of the magnetic field.Results MTX content of the right brain in the presence of magneitic field 0.56±0.02 was 9.3 times as many as that of the right brain in the absence of magnetic field 0.06±0.02 at 45 min.There was significant difference in MTX contents between the right and left brain at different time points (P<0.01).At the same time point,MTX content of the right brain was significantly higher than that of the left brain(P<0.01).Conclusion In the presence of magnetic field,FM HAS MTX can be targeted to distribute successfully in the brain.