Mechanics properties of lime-steel slag stabilized soil for pavement structures are investigated. Firstly, the chemical composition of the fine grain steel slag is analyzed by spectral analysis test. In view of the materials compositions, 5 kinds of mix proportion projects are defined. Compaction tests of all mix proportion projects are carried out in different water conditions to obtain the optimum moisture contents. Then the optimum mix proportion project is demarcated by the unconfined compressive strength test and the compression rebound modulus test. Finally, the pavement structures design for a highway of lime-steel slag stabilized soil road sub-base is made. As comparisons, the pavement structures of other types of lime industrial wastes stabilized soil road sub-base are computed. It is shown that lime- steel slag stabilized soil is suitable for flexible pavement or semi-rigid pavement because of its good strength and rigidity which can effectively reduce thickness of the lower pavement and basic deflection.