ITER toroidal field (TF) systems consist of 18 independent coils that are around the torus, whose primary function is to confine the plasma particles. The TF coil conductor is a cable-in-conduit conductor (CICC) made up of superconducting, Nb 3 Sn-based strands mixed with pure copper strands. As the only supplier in China, Western Superconducting Technologies Company, Ltd. (WST) will supply TF Nb 3 Sn strands using internal tin route for ITER, and over 6,000 km of Nb 3 Sn strands have been produced in the past four years. Main performance of Nb 3 Sn strands, including critical current, n value, wire diameter, Cu/non-Cu ratio, hysteresis loss and RRR are reported and analyzed in this paper.