Abstract: Accurate assessment of dynamic compaction reinforcement effect for crushed rock soil fill foundation in moun- tainous areas is a common concern problem. The reinforcing mechanism of dynamic compaction for crushed rock soil fill foundation is analyzed. Then, based on the characteristics of crushed rock soil fill foundation in mountain areas, the validity and rationality of formula estimating method and test method to evaluate dynamic compaction reinforcement effect are studied. At the same time, an actual project is analyzed for further discussion. The results indicate that using the formula estimating method to evaluate the dynamic compaction reinforcement effect for crushed rock soil fill foundation in mountainous areas has limitations. While a single test evaluation method has high cost and low reliability. Only to evaluate the reinforcement effect by applying the Rayleigh waves, static load tests and dynamic penetration tests comprehensively is a reliable and economy method, and the comprehensive evaluation by using the bearing capacity of foundation and deformation modulus is a reasonable and applicable judging criterion for the effective improvement depth.