Abstract: The mixed polymer brushes which combine poly(2-methyl-2-oxazoline)(PMOXA) with anti-protein adsorption properties and poly(acrylic acid)(PAA) with stimulus-responsive properties were prepared on the material surfaces (including glass, silicon, and gold) by using poly(dopamine)(PDA) as an anchor. The surface chemical composition and thickness of the mixed polymer brushes were characterized by X-ray photoelectron spectroscopy (XPS) and variable angle spectroscopic ellipsometry (VASE). The hydrophilicity of the polymer brush surface was studied by water contact angle (WCA). Choosing pH = 9 and I = 0.01 mol/L (I is ionic strength) as the fibrinogen adsorption conditions, and pH = 9 and I = 0.15 mol/L as the fibrinogen desorption conditions. The adsorption and desorption behavior of fibrinogen on mixed polymer brushes was studied qualitatively and quantitatively by fluorescence microscope and surface plasmon resonance (SPR). The results showed that when the environmental pH = 9 and I changes from 0.01 mol/L to 0.15 mol/L, the surface of the mixed polymer brushes would change from a relatively hydrophobic state to a hydrophilic state. Increasing the degree of polymerization of PMOXA would reduce the amount of protein adsorption of the mixed polymer brushes, and would also significantly improve the protein desorption rate of the mixed polymer brushes. The mixed polymer brush prepared by sequential grafting PMOXA with a degree of polymerization of 60 and PAA with a degree of polymerization of 90 in a mass ratio of 3∶2 achieved the desorption rate of 83.5% for fibrinogen.