||The poly(ethyleneglycol) (PEG)-therapeutic protein conjugates are widely used as drug delivery. However, the anti-PEG antibodies raise concerns about the PEGylated therapeutics application . Compared to the PEG-conjugation, conjugation of human serum albumin (HSA) is an attractive emerging strategy for the extension of the serum half-life of a therapeutic protein . To clarify whether the site-specific albumination is an effective strategy, alternative to PEGylation, comparision of serum half-life extension is required. However, the serum half-lives of PEGyalted and albuminated proteins have not been directly compared. In this study, We achieved that the site-specific PEG- or HSA-conjugation to superfolder green fluorescent protein (sfGFP) and then, compared their serum half-lives.