This paper proposes a composite metric for analyzing economic inequality reflected in prehistoric burials by integrating the value of burial goods with the labor investment required for burial construction. This approach helps mitigate interpretive biases that arise from relying on a single dimension of burial wealth assessment. To address the common challenge of small sample sizes in prehistoric burials, we adopt bootstrap resampling and apply appropriate small-sample corrections to the resulting Gini coefficients. Building on the above methods, this paper uses extensive prehistoric burial data from a site on China’s Liyang Plain to trace diachronic patterns of economic inequality. The study reveals diachronic patterns of economic inequality, showing that increase in burial wealth inequality was likely tied to hydraulic infrastructure projects and that ritual power concentrated wealth more effectively than political-military power.