The invention relates to a pegylation recombinant human granulocyte colony stimulating factor purification method. Particularly, the purification method optimizes separation and purification of PEG-G-CSFs (pegylation granulocyte colony stimulating factors) in a cation-exchange chromatography manner, PEG-G-CSF stock solution is prepared by proper buffer solution in a replacement manner, HPLC (high performance liquid chromatography) and the PEG-G-CSFs can be acquired by the aid of one-step column chromatography purification and replacement of the buffer solution, and the electrophoresis purity of the PEG-G-CSFs is 98% or more. According to a purification process, a process route is simplified, production time is saved, protein recovery rate is high, the purity of obtained stock solution is high, medicinal preparations can be prepared by adding proper medical auxiliary materials, and the purification process is quite suitable for large-scale industrial amplifying production.