We present an entanglement concentration protocol (ECP) for unknown less-entangled states resorting to the quantum-dot spins in double-sided optical microcavities.The protocol exploits an error-detected mechanism to overcome local computational errors,which is intrinsically robust to experimental imperfections and more practical than previous ECPs for QDs.We discuss the performance of the ECP with current experimental parameters,and the results show a success probability of 45％ for the present scheme without recycling can be achieved.The ECP could provide a promising building block for solid-state quantum repeaters and quantum networks in the future.