Objective: To study the effect of Poloxamer 188 after the retest period on its quality and cell culture.Methods: The determination of p H, endotoxin content and cell culture and the identification of Raman spectra to poloxamer 188 at 6, 24 and 36 mo after the retest period were performed to evaluate its effects on cell growth and recombinant protein expression as a medium component.Results: The p H, endotoxin content and Raman identification of poloxamer 188 within 36 mo after the retest period met the related standardsPoloxamer 188 within 24 mo after retest date showed no differences in cell growth and viability and the protein expression compared with one within retest date, however, those indicators were all decreased when poloxamer 188 stored for 36 mo after retest date was used.Conclusion: The retest period of poloxamer 188 is suggested to be 24 mo after retest date as a component for serum free medium.