Abstract: 【Objective】 To investigate the regulatory roles of hydrogen（H2） and strigolactones（SLs） and their interaction in the roots of tomato seedlings under salt stress.【Method】 Tomato（Solanum lycopersicum L.‘Micro-Tom’） was used as the experimental material,and was grown in an artificial culture chamber substrate.Based on the optimum concentration of hydrogen-rich water（75%）,the treatments are as follows: 100% Hogland（CK）,salt stress（NaCl）,NaCl + HRW,NaCl + GR24（SLs synthesis）,NaCl +HRW+ TIS108（SLs synthesis）.Root related parameters,SLs content,and the expression of SLs biosynthesis related genes were determined.【Result】 Under salt stress,75% HRW treatment significantly increased root length,fresh weight,and dry weight of tomato seedling roots.Meanwhile,GR24 and HRW promoted root morphological parameters（root length,root surface area,root volume,root/shoot ratio,etc.） and root activity of tomato seedlings under salt stress.However,the beneficial roles of HRW were blocked by TIS108（SLs inhibitor）.Thus,SLs may be responsible for H2-regulated salt stress tolerance in the root of tomato seedlings.Additionally,HRW treatment increased endogenous SLs levels in tomato seedling roots under salt stress.HRW treatment significantly up-regulated the expression levels of SLs biosynthesisrelated genes SlCCD7,SlCCD8,SlD14 and SlMAX1 under salt stress.【Conclusion】 SLs may be involved in H2-induced salt tolerance in the root of tomato seedlings.