The present invention relates to a mutant G-CSF fusion protein. The mutant G-CSF fusion protein is a fusion protein having the activity of stimulating the proliferation of neutrophilic granulocytes, and having a basic structure of G-CSF/carrier protein or carrier protein/G-CSF; wherein the G-CSF moiety comprises multipoint substitutions thus resulting in changes in biological activity and binding affinity. Compared with existing products, the mutant G-CSF fusion protein in the present invention has longer half-life and higher biological activity. Administration of the pharmaceutical preparation containing this mutant G-CSF fusion protein could be used in the treating neutropenia.