  We present a single-photon entanglement concentration protocol for
long-distance quantum communication with quantum nondemolition detector. It is
the first concentration protocol for single-photon entangled states and it dose
not require the two parties of quantum communication to know the accurate
information about the coefficient $\alpha$ and $\beta$ of the less entangled
states. Also, it does not resort to sophisticated single-photon detectors,
which makes this protocol more feasible in current experiments. Moreover, it
can be iterated to get a higher efficiency and yield. All these advantages
maybe make this protocol have more practical applications in long-distance
quantum communication and quantum internet.
