The kinetics of adsorption of phospholipids to the air/water interface at 20 degrees C induced by surfactant protein C (SP-C) was studied. A two-step assumption was proposed to describe the mechanism of phospholipids adsorption: (1) diffusing of the lipid vesicles from the bulk to the subsurface, (2) forming the lipid-protein aggregations by interaction between phospholipids and SP-C and spreading at the surface. On the basis of the change characteristic of surface pressure ()-time (t) isotherm, the whole adsorption process was divided into three stages in which it is controlled by adsorption, diffusion and diffusion together with adsorption, respectively. The corresponding kinetic models were developed and verified by the experimental data reported in literature [Ross et al., Eur. Biophys. J. 2002;31:52-61]. The results show that the data corresponding to each stage can be described well by growth model (AAD%=1.0%), diffusion model (AAD%=4.1%), and the pseudo-second-order model (AAD%=1.8%), respectively.