The Cd is a non - essential metal and highly toxic to organisms, even in very low concentration. In the coastal marine ecosystems, the removal of heavy metal from the contaminated water, phytoremediation obtained a great concern in the recent years. Sesuvium portulacastrum is a halophyte and considered as a potential species of phytoremediation of heavy metal in the coastal regions. Cadmium (Cd) accumulation, subcellular distribution and chemical forms in the roots, leaves and stem of Sesuvium portulacastrum were studied hydroponically under exposure to 50 µM - 600 µM Cd stress for 28 days to investigate the potential accumulation capability and tolerance mechanisms. The Plants demonstrated good growth condition until Cd stress of 200 µM, then their growth significantly (P< 0.05) reduced with increasing Cd concentrations. Cd accumulation in Sesuvium portulacastrum root tissues showed that the bioconcentration factor was >10 and the highest bioaccumulation factor was in the 50 µM and 100 µM of Cd stress, suggesting a strong ability to absorb and accumulate of Cd. In addition, the subcellular distribution of Cd fractionation in aerial parts showed the following order of distribution soluble fraction>cell wall>organelle>cell membrane and soluble fraction was predominant in roots. Moreover, Cd speciation in leaves and stems mainly composed of NaCl and deionized water extracted form, suggesting a strong binding ability with pectin and protein as well as organic acid. We can presume that the cell wall fixation and vacuole compartmentation is the main fundamental mechanism to resilience to Cd toxicity and considered as a potential phytoremediator because of solid bioaccumulation.