The Na-SrSiO3 as a potential high-conductivity ionic conductor for intermediate temperature solid oxide electrochemical cells (SOECs) has drawn much attention recently. Some of these studies questioned the feasibility of Na doping and therefore the creation of oxygen vacancies, while others suggested an alternative phase responsible for the ionic conduction. In this study, a systematic investigation was carried out to understand the ionic conduction in Na-SrSiO3. Through insitu high-temperature X-ray diffraction, thermal analysis, microstructural characterization, and electrical conductivity measurement, Na-SrSiO3 was shown as a two-phase material, one being slightly Na-doped SrSiO3 and another being amorphous Na2Si2O5. The former was an electrical insulator whereas the latter was a good ionic conductor. It was also found that the amorphous Na2Si2O5 phase was unstable at the temperature 500 degrees C, crystallizing into the insulating polycrystalline Na2Si2O5 which causes conductivity to bend-over at higher temperatures. A preliminary Ab Initio Molecular Dynamics (AIMD) simulation suggested that the amorphous Na2Si2O5 be predominantly a Na+ conductor.