[Objective] Riverbed overburden, which is characterized by significant thickness and complex composition, constitutes a poor coarse-grained soil foundation. Works built upon such overburden require reinforcement treatment. Dynamic compaction is a rapid and effective ground improvement technique. However, when applying dynamic compaction to riverbed overburden, there is currently a lack of reasonable methods for evaluating its reinforcement effectiveness, and it is difficult to accurately obtain the engineering mechanical properties after compaction. [Method] Based on a dynamic compaction project for overburden reinforcement and drawing on the concept of the pressuremeter modulus equivalent density method, this study employed a combination of in-situ density tests, field pressuremeter tests, laboratory model pressuremeter tests, and laboratory unit mechanical tests. A comprehensive evaluation method for the effectiveness of dynamic compaction treatment on overburden was proposed by comparing and analyzing the in-situ density and pressuremeter modulus of the overburden before and after dynamic compaction to evaluate the reinforcement effect. The mechanical property indicators of the overburden after compaction were obtained. [Results] (1) The in-situ dry density in the shallow layers of Test Zone Ⅰ and Test Zone Ⅱ increased by 7.8% and 5.3%, respectively, after compaction, indicating that dynamic compaction significantly improved the in-situ density of the shallow overburden. (2) Within the upper 6 m, both the in-situ density and pressuremeter modulus of the overburden showed improvement. Below 6 m, the pressuremeter modulus remained close to pre-compaction levels. This demonstrated that dynamic compaction primarily enhanced the shallow layers of the overburden, with negligible reinforcement effects observed in deeper layers. [Conclusion] The proposed comprehensive evaluation method combines qualitative and quantitative assessment by comparing the pressuremeter modulus and in-situ density before and after dynamic compaction; together with laboratory unit mechanical tests, it can accurately obtain the mechanical parameters after compaction and provides an economical and efficient approach for assessing overburden treatment effects and engineering characteristics.