For a long time, the settlement of embankment body is a main research problem of highway and railway roadbeds. Embankment body is mainly composed of unsaturated soils, and its deformation includes three components, namely, the deformation resulting from the instantaneous compaction, the deformations of primary consolidation and secondary consolidation deformation. However, primary and secondary consolidations influencing each other are not two completely independent processes. So the deformations of embankment body are the results of unsaturated creep and consolidation coupling. Based on the results of uniaxial compression creep test on red layers, the theories of single variable of unsaturated soil and embankment settlement of unsaturated are put forward. And at the same time, through centrifuge tests and numerical simulation of centrifuge tests, relations between settlement and fill height, post-construction settlement and time, are studied for embankment body on various compaction coefficients, and final construction settlements are predicted. Results show that the simulated results are consistent with the predicted results by the centrifugal experimental data, indicating that the theories are correct.