  We present a deterministic entanglement purification protocol (EPP) working
for currently available experiment technique. In this protocol, we resort to
the robust time-bin entanglement to purify the polarization entanglement
determinately, which is quite different from the previous EPPs. After
purification, one can obtain a completely pure maximally entangled pair with
the success probability of 100%, in principle. As the maximal polarization
entanglement is of vice importance in long-distance quantum communication, this
protocol may have a wide application.
