Abstract: This experiment was conducted to study the effects of zeolite on enzyme activity, osmotic adjustment substances and ions of tomato seedlings under NaCl stress. Results indicated that addition of zeolite increased SOD、CAT activity and Pr contents, decreased Pro content in leaves, but increased soluble sugar content in leaves, K content in roots, stems and leaves, and Ca content in leaves. Zeolite addition decreased Ca content in roots and stems, Mg and Na contents in roots, stems and leaves. All the indices indicated that the application of zeolite can reduce the NaCl stess on tomato seedlings at the stated concentration.