Structural properties of Na2O-9SiO2 liquid under compression are studied by computer simulation. The local structure characteristics as well as topology of SiOx are investigated via pair radial distribution function, coordination number, Si-O bond distance and O-Si-O bond angle distribution. The incorporation mechanism of Na+ ions in Si-O network as well as their role in network structure will be clarified. Specially, influence of Na+ ions to the topology of SiOx units will be explained in detail.