OBJECTIVE To improve and estabilish a HPLC assay of leucogen.METHODS A HPLC method was improved by changing the contents of mobile phase.RESULTS Acetonitrile-phosphate buffered soulution(PBS,pH6.8)-glacial acetic acid-phosophoric acid(38∶62∶0.12∶0.07)was the best mobile phase condition.CONCLUSION The established method was accurate,reliable and economical.