Abstract: Cd polluted salinity soil in Tianjin sewage-irrigated area was used as the study object, chemical form distribution of Cd and its influencing factors were analyzed. The studied salt type was mainly NaCl and Na2SO4, 7 salinities were conducted, added mass fractions were 0% (CK), 0.2%, 0.4%, 0.6%, 1%, 2% and 5%, the first three kinds of Cd form (exchangeable, carbonate bound and Fe Mn the oxidation state) were studied by Tessier continuous extraction method, and the distribution law was obtained. The results showed that under the condition of adding NaCl, the carbonate bound state > exchangeable state > Fe Mn oxidation state, the exchangeable state content was significantly correlated with salinity, total heavy metal, pH value and organic matter. Under the condition of adding Na2SO4, the Fe Mn oxidation state > exchangeable state > carbonate bound state, the exchangeable state and carbonate bound were significantly correlated with pH value and organic matter, and the Fe Mn oxidation state was negatively correlated with pH value. There was also a correlation between salinity and Cd forms. Under the condition of adding NaCl, pH value had important effect on exchangeable Cd content; and organic matter had important influence on the carbonate bound state; the content of Cd had important influence on the Fe Mn oxidation state. Under the condition of adding Na2SO4, organic matter had important influence on exchangeable Cd content; pH value and organic matter had important effect on carbonate bound state; CEC had important influence on Fe Mn oxidation state. The distribution pattern of Cd and the effects of soil physical and chemical properties on Cd forms obtained by this study could provide a theoretical basis for the prevention and control of soil heavy metal pollution and for the ecological risk assessment.