Abstract： We proposed a new method to study adsorption dynamics by surface enhanced Raman scattering (SERS). A simple theortical model of adsoption dynamics for solid-liquid interfaces was established. We analysed the time dependence of SERS intensity and further deduced the parameter of adsorption dynamics, such as constant of adsorption speed, adsorption activation energy. As an example, we studied the adsorption dynamics of P-amino-benzoic acid adsorped on the silver colloid. The results show that the faster process of the time dependence of SERS are related to the adsorption process. From the experimental data and our theoretical model, the constant of adsorption speed were deduced. We believe that the study of adsorption dynamics by SERS is very promising.