A first-principles molecular-dynamics study of liquid NaSn alloy is presented. The structural properties (static structure factor, bond angle distribution) are discussed. The calculated static structure factor is in good agreement with that from neutron diffraction experiments. The calculations show a tendency of network formation of threefold and fourfold coordinated tin atoms in the liquid. Tetrahedral Sn₄ complexes-Zintl anions [Sn₄⁴])-which are typical structural units in solid NaSn are nearly absent in the liquid. As a consequence of the network formation there is an indication of a bimodal bond angle distribution for the tin atoms.