Abstract: To explore the evolution mechanism of tidal flats under the influence of multiple factors, a cross-shore profile numerical model is developed based on vegetation growth and tidal processes. For a bare flat driven by tides, a general convex cross-shore profile is obtained after medium-to long-term simulation. Sediment supply determines the width of mudflat, and a higher sediment supply leads to a wider and gentler mudflat. For marsh flats, different spatial distribution of biomass affects tidal hydrodynamics differently. At the upper intertidal flat, the flow reduction effect with parabolic distribution of biomass production is stronger than that with linear distribution, and it is converse at the lower intertidal flat. A scarp is simulated at the edge between the bare flat and marsh flat, and it moves seaward as the sediment deposition on intertidal flats.