It is in line with the concept of sustainable development to fill embankment with mudstone waste slag. However, the property of mudstone softening and disintegrating in water may affect the operation quality of the road. Relying on the Hechang Highway project, the engineering properties of mudstone filler and the settlement characteristics of embankment are studied by centrifugal model test and field test. The results showed that: under Optimum moisture content, the settlement of mudstone embankment mainly occurred in the filling stage (accounting for 62.96% of the total), and it could reach stability after 24 months of operation. The embankment settlement in cross-section showed the trend of "upward concave", and the settlement difference is not significant. Under continuous rainfall condition, the settlement mainly occurred in the operation stage (accounting for 49.05% of the total), and it could reach stability after 44 months of operation, in cross-section showed the trend of "M", the largest settlement at the shoulder. The trend of the basement earth pressure and the settlement on top of embankment is basically the same. Under continuous rainfall condition, the basement earth pressure is more concentrated toward the road centerline. It can be seen that rainfall has a certain influence on the strength and stability of mudstone embankment. The above research results provided a reliable basis for the design of embankment filled with mudstone waste.