The invention relates to an elaborate purification method of recombinant human interleukin 11 (rhIL-11). Fusion protein is desalinated by utilizing a dextran gel G-25 desalination column, the desalinated liquid is collected to carry out the cascade sample loading of negative and positive ion exchange chromatographic columns, after the sample loading is finished, the desalinated liquid is eluted by the specific Gly-NaOH buffer solution, and the collected main eluted protein solution is desalinated by the dextran gel G-25 desalination column, so that a high-purity protein sample is obtained. The method is suitable for large-scale production and is characterized in convenient operation, short production cycle, high purity of products, stable technique, etc.