The purpose of this study is to investigate weighted compaction density according to a leading density in truck, a compaction density of solid waste and composition ratios of solid waste fur calculation of a capacity of the landfill sites. The experiments for calculations of in-place density at landfill site have been conducted in S landfill site at B City. The size of vessel for measuring the compaction density was $1m^3(1m{ imes}1m{ imes}1m)$. The experiment tests have been carried out methods (1 time for bulldozer and 4 times for compactor) that do contain all of specification at the landfill site. Average of the loading density at the landfill site was $0.264;ton/m^3$ ($0.113{sim}0.487;ton/m^3$). When the loading density for each compositions was compared, the composition of the highest average loading density ($0.474;ton/m^3$) was miscellaneous wastes. The composition of the lowest average loading density ($0.120 ton/m^3$) was general solid waste. The reported results indicated that the compaction density at the landfill site was $0.538;ton/m^3$, which was calculated with weighted incoming ratios of compositions. The ranges of the density for each composition were from $0.021;ton/m^3$ to $0.221;ton/m^3$. When the compaction density for each composition was compared, the composition with the highest average compaction density ($0.221;ton/m^3$) was miscellaneous wastes. The composition with the lowest average compaction density ($0.021;ton/m^3$) was general solid wastes.