A new optimized highway earthwork allocation model from mass-haul diagram idea is built in this study. A mass-haul diagram is a kind of traditional manual method, but it is visualized and convenient for earthwork allocation. With it, the earth moving operations can be represented as discrete events systems, and an ant colony optimization (ACO) algorithm is developed as a system to be equipped with the model. It was shown that the model developed in this study was effective and could increase earthwork allocation efficiency. The model can compute cut and fill quantities and generate the optimal earthmoving plan automatically.