Microsegregation within the columnar dendritic array is analyzed by performing a two-dimensional phase-field simulation. The influence of microstructure morphology on microsegregation is studied for various backdiffusion conditions. Under the condition of no backdiffusion, it is found that for the region without second dendrite arms the simulation result agrees well with the Scheil equation, but for the region with well developed second dendrite arms there is a severe deviation. This deviation is attributed to the dendrtic coarsening and the inhomogeneity of interdendritic liquid concentration caused by various interface curvatures. Under the condition of moderate back diffusion, it is found that the effect of dendritic morphology on microsegregation can be accounted by enhancing the Fourier number which characterizes the solid-state diffusion. However, this effect decreases with enhancing the back diffusion of the system. (C) 2008 Elsevier B.V. All rights reserved.