摘要： Green chemistry gained special attention for the environmental safety. In addition, green synthesized plant based nanoparticles for the degradation of industrial pollutant dye also received special focuses. Thus, photocatalytic activity of nanosized zinc oxide (Sj-ZnONps) synthesized by a simple co-precipitation method using sodium hydroxide, zinc nitrate, and Suaeda japonica extract as starting materials was carried out. The reaction was implemented in comparatively low temperature (50oC) without further calcination. The absorption spectrum demonstrated an extinction peak at ~362 nm, which is characteristic to the ZnO nanoparticles. Field-emission transmission electron microscope revealed smaller agglomeration of hexagonal Sj-ZnONps (~100 nm). X-ray diffraction patterns exposed polycrystalline ZnO with hexagonal wurtzite structure. The self-assembly of Sj-ZnONps was achieved due to the capping of phytoconstituents present in extract as evident from Fourier-transform infrared spectroscopy analysis. The photocatalytic degradation of Sj-ZnONps was estimated in reduction of methylene blue (MB). The reaction mixtures comprising of MB, S. japonica extract and Sj-ZnONps had the most significant decrease of MB by 54 %. In conclusion, the Sj-ZnONps can be used as a photocatalyst for decomposition of organic pollutions present in water.