The corrosion behavior of low carbon steel welded joint was performed using salt spray and immersion test which is follow ASTM G-31 and B-117 standards. Four different edge shape designs for weld joint preparation was selected namely; straight, single V, double V and single groove edge were selected to weld 12 mm low carbon steel plate. The duration of exposure time was 7 days in 3.5 wt.% NaCl solution to simulate marine environment application. After corrosion test the surface degradation of the welded joint was studied by visual inspection and SEM analysis. The experimental results show that the corrosion behavior of welded joint was more severe under salt spray test compared with of immersion test particularly because difference environment mechanism. The morphological characteristics of the surface of welded joint show difference in pit characteristics.