Abstract: Objective To fractionate mouse liver phosphoproteome by two-dimensional liquid chromatography. Methods The phosphoproteins were extracted from the lysates of normal mouse livers with phosphate metal affinity chromatography resin. The phosphoproteins were exchanged by the initial buffer and separated by chromatofocusing in the first dimension. The fractions with pH value between 8.5 and 4.0 were separated by non-porous silica reverse-phase high-performance liquid chromatography. Finally, the UV maps were converted into gel maps by ProteoVue software. Results The phosphoproteins of mouse liver were successfully extracted and fractionated by two-dimensional liquid chromatographic fractionation after concentration and desalting. The pI/UV map of mouse liver phospho-proteomic was obtained successfully. There were 16 fractions with pH between 8.5 and 4.0 after chromatofocusing in the first dimension and the UV maps of each fraction were converted into pI/UV gel maps. Conclusion Combination of phosphoprotein enrichment and two-dimensional liquid chromatographic fractionation is an effective approach of phosphoproteomic studies.