The invention discloses a method for remediating soil contaminated by heavy metals such as cadmium by combining in-situ leaching, deep-layer fixing and phyto-extracting. According to the method, the heavy metals are leached into a deep layer along with a leaching solution through the in-situ leaching in a surface layer and are fixed in the deep layer, then willow with the heavy metal accumulation function is planted after organic fertilizer is applied, and therefore the residual heavy metals can be further removed, and the soil function can be restored; the heavy metals in a plough layer are leached to the deep layer, the absorption of crops to the heavy metals is reduced, the heavy metals which are leached to the deep layer are fixed, underground water is not polluted, and therefore the residual heavy metals can be further removed through phytoremediation, and the soil function can be restored; an iron-containing compound used in the method does not destroy the soil structure and can serve as a rice field soil conditioner; and compared with the phytoremediation, the method has the advantage that the remediation efficiency can be improved, and compared with leaching remediation, the method has the advantage that the steps of excavating, stirring, separating and the like can be omitted. The invention provides the remediation method. The remediation method has the advantages of being short in time, low in cost and high in efficiency and having a wide application prospect in the field of remediation of a large-scale farmland contaminated by the heavy metals.