Abstract: Double antibody sandwich-type ELISA was used to detect rhG-CSF in serum to study the pharmacokinetics of rhG-CSF, PEG-rhG-CSF and rHSA-hG-CSF in mice and to confirm that PEGlyation and albumin fusion of rhG-CSF technology can prolong half-life of G-CSF. Pharmacokinetic parameters were calculated with 3P87 software. T_1/2s of rhG-CSF, PEG-rhG-CSF and rHSA-hG-CSF are 2.1, 14.2 and 10.6 h, respectively. T_1/2s of PEG- rhG-CSF and rHSA-hG-CSF are 7, 5 times than T_1/2s of rhG-CSF, respectively. T_peaks of PEG-rhG-CSF and rHSA-hG-CSF are 15, 13 times than T_peak of rhG-CSF, respectively. The result of ELISA indicates that PEGlyation and albumin fusion of rhG-CSF technology can prolong half-life of G-CSF.