We propose a simple experimental scheme in which an unknown two-qubit state is faithfully and deterministically teleported from Alice to Bob.The scheme is constructed with four photons from parametric down conversion, linear optical elements,and conventional photon detectors, all of which are available in current technology.It is shown that the probability of successful teleportation ideally reaches 100% based on single-photon two-qubit-assisted Belstate measurement,which can distinguish all four Bell-states simultaneously via conventional photon detectors.By generalizing the scheme,the teleportation of an unknown multi-qubit system can also be realized.