A greenhouse research was conducted to evaluate the ameliorative effects of zinc application on soybean photosynthetic parameters, leaf relative water content (RWC), relative electrolytic leakage (REL), chlorophyll contents (Chl), and leaves and roots lipid peroxidation rate under salinity stress (0, 33, 66 and 99 mM NaCl). The results revealed that zinc application on plants exposed to salinity stress caused a noticeable enhancement of photosynthesis (Pn) by 110%, water use efficiency (WUE) by 54%, mesophyll efficiency (ME) by 98% and quantum yield () by 102% compared with plants exposed to salinity stress alone. The chlorophylls a, b and total chlorophyll content and relative water content were significantly reduced with increasing NaCl salinity. The highest REL and lipid peroxidation were occurred at the highest salinity level.