During the screw conveying process, the distribution and resident time of materials are very important factors for optimum operation conditions. In this research, peanut nut, young soybean and chinese mushroom with different screw speed of the two-stage transportation hae been tested to analyze the residence time distributions and the extent of axial mixings. The results showed that the stability of outlet curve was advanced by increasing the transport speed. Therefore, the resident time decreased and the spread of residence time distribution concentrated. The mixing and dispersion of this machine was not significantly effected by different materials and transport speeds.