Presented in this paper is a theoretical analysis for a pulsed bicomponent contaminant emission into a free-surface wetland flow.Basic equations are introduced for bicomponent contaminant transport in wetland flow under the combined action of advection, mass dispersion, and ecological reaction at phase average scale.The effect of ecological reaction is separated from hydrodynamic effect via a set of widely used transform.Analytical solution for evolution of depth-averaged concentration is rigorously derived and illustrated, with a limiting case covering the known solution for single component contaminant transport.It is found that the depth-averaged species concentration of bicomponent contaminant can approach an equlibrium status which is determined by distribution coefficient.