Abstract The structure of sodium metasilicate has been determined for the first time based on a first-principles calculation. The total energy expressed in the local-density approximation is minimized using a preconditioned conjugate gradient algorithm. The Vanderbilt ultrasoft pseudopotenial scheme is adopted to improve the computational efficiency. All the structural parameters obtained agree very well with experimental results. Also, the band structure and electron density of states are calculated and compared with experiments and other theoretical studies.