n-Si/Cu2SnS3(CTS) heterojunction solar cell has been fabricated in this work using different doping concentration of Na into CTS thin films. The pure raw powders of Copper, Tin, Sulphur and NaF have been ball milled, pressed and heated to form CTS pure and Na doped targets. The deposition of CTS thin film pure beside 1%, 3% and 5% Na doped CTS thin film have been held by pulsed laser deposition technique. The different properties of CTS thin films have been studied using different analyse methods and it has been observed that the properties of these CTS thin films are strongly dependent on Na concentration. Doping CTS thin films with 1% Na has enhanced the crystallinity and the optical absorption. The solar cells based on n-Si/p-CTS heterojunction present different power conversion efficiency according to Na concentration in CTS thin films. The best photovoltaic performance has been obtainable by Al/n-Si/CTS(1%Na doped)/Ag solar cell with open circuit voltage of 300 mV and power conversion efficiency of 1.02%.