Objective To study the distribution of the lactate dehydrogenase isoenzyme in different tissues of field voles ( Microtus fortis ). Methods The samples were studied by polyacrylamide gel electrophoresis (PAGE) and stained by sodium lactate. Results There was only LDH 5 in plasma of field voles from all three regions and in sera of field voles from Dongting region and from Ningxia Qingtongxia region. There were two kinds of LDH isoenzymes(LDH 1 and LDH 5)in sera of field voles from Dongbei region. Five kinds of LDH isoenzymes were found in kidney and lung of field voles from three regions and in liver of field voles from Dongbei region, but LDH 5 was dominated in liver of the two other field voles(more than 95%). Conclusion\ LDH isoenzymes of field voles from Dongbei region were different to some extent from the two other regions.