To study the feasibility of applying cement-silica fume-stabilized un-aged steel slag-crushed stone materials for base layer paving, the volume expansibility of steel slag was treated with silica fume. The experimental results showed that the minimum silica fume content for suppressing the expansion rate of steel slag was 2%. Based on this premise, the orthogonal test design method was adopted to explore the mechanical properties and frost resistance of cement-silica fume-stabilized un-aged steel slag-crushed stone base layer materials. The test results indicated that the main influencing factors on the 7-day unconfined compressive strength and splitting strength of the cement-silica fume-stabilized un-aged steel slag-crushed stone base layer materials were the cement content, while the main influencing factors on the 28-day unconfined compressive strength, compressive resilient modulus, and frost resistance were the steel slag content.