Abstract: By orthogonal test based on pavement performance, 4 influencing factors of lime-steel slag stabilized soil were studied. The results showed that lime content is the most influential factor of the early compression strength,the steel slag is relatively small. But the factor of steel slag content is more and more prominent of the later compression strength. And the influence of the steel slag particle size on growth rate of the late strength is more remarkable. The compared results showed that the value of unconfined compression strength and the value of CBR of the lime-steel slag stabilized soil are so big to meet the requirements of 《Specifications for Design of Highway Subgrades》(JTG D30-2015) and 《Technical Guidelines for Construction of Highway Roadbases》(JTG/T F20-2015), and showed that the steel slag can replace some limes or some cements to be used to fill highway roadbed.