Erosion of mixed cohesive and noncohesive sediments is studied using the erosion test instrument SEDFlume. The sediment mixtures are composed of well-sorted quartz sand (0.25-0.5 mm) and one of the three used muds:kaolinite, kaolinite-bentonite and Mississippi River muds. The mud contents cover from 0 to 100％. The measured data of erosion rate and bed shear stress are used to examine the segmented linear, nonlinear, and exponential erosion models. The parameters of each erosion model are related to the physical properties of sediment mixtures, including clay fraction, mud fraction, mixture dry density, and mud dry density. It is found that the three models can fit well with the data, and their parameters have strong relations with the mud fraction and mud dry density, to a less extent with the clay fraction, but not with the mixture dry density.