The application of steel slag in road materials is one of the important ways for the large-scale consumption of steel slag. Cement steel slag stabilized soil is a new type of pavement base material. In this paper, the effects of cement dosage and steel slag content on the unconfined compressive strength and splitting strength of cement steel slag stabilized soil were studied. At the same time, the effect of steel slag content on the drying shrinkage performance of cement steel slag stabilized soil was also discussed. The results show that with the increase of steel slag content, the unconfined compressive strength and splitting strength of cement steel slag stabilized soil gradually increase, the flexural-compressive strength ratio increases first and then decreases, and the drying shrinkage coefficient gradually decreases. With the increase of cement dosage, the 28 and 90 d unconfined compressive strength and splitting strength of cement steel slag stabilized soil gradually increase. When the cement dosage increases to 5% (mass fraction), the flexural-compressive strength ratio decreases to a certain extent. The engineering application research is carried out by using the mixture ratio (mass fraction) of 5% cement (extra-mixing), 60% of steel slag, and 40% of soil. The test section has been tested on site, and the engineering application effect is good and the economic benefit is good.