Abstract: To solve the resource-constrained project scheduling problem (RCPSP), an optimization algorithm combined discrete particle swarm optimization (DPSO) with extended serial scheduling scheme is presented.In DPSO the location of each particle represents priorities of activities.Cross strategy and local search technology are adopted when updating the particle positions, which can ensure discreteness, increase the diversity of particles and avoid premature during iteration.The location of each particle is transformed to a feasible schedule by the extended serial scheduling scheme.The actual calculation shows that extended scheduling scheme can accelerate the convergence process obviously and improve the precision.It can be concluded that this algorithm is valid for RCPSP.