To investigate the differences in compaction characteristics of asphalt mixtures caused by thickness changes, three types of asphalt mixtures, namely SMA-10, OGFC-10, and AC-10, were selected. Specimens with different thicknesses were prepared using Marshall compaction and roller-compacted methods, and the effects of rigid and flexible lower layers were considered. Volume indices and compaction energy indices were comprehensively used for evaluation. It is found that the volume parameter changes of different gradation asphalt mixtures vary under changes in molding thickness and compactive effort. For dense graded mixtures (SMA-10 and AC-10) on a rigid lower layer, when a density of 93% is achieved, compaction energy and the number of compactions show a decreasing then increasing trend with decreasing thickness, with 3 cm being the critical point. For skeleton-void mixtures (OGFC-10), compaction parameters increase with decreasing thickness. When SMA-10 is overlaid on an asphalt pavement to achieve 93% density, the compaction energy and number of compactions also show a decreasing then increasing trend with decreasing thickness. Considering the overlay characteristics of both rigid and flexible pavements, the recommended optimal paving thickness for SMA-10 is 2 ~ 3 cm. In addition, for the same thickness of thin overlay on a flexible lower layer, more compaction efforts are required to achieve 93% density compared to a rigid lower layer. The research results provide a theoretical basis for optimizing thin overlay compaction processes and quality control.