Abstract: Abstract: Crop residues are important biological resources that can be used as sources of renewable energy, feed and other industries. After crushing crop straws into particles, belt conveyor is a common transportation way of the straw particles for production process. However, the quantity of mass transferred straw with belt conveyor was affected by various factors, whose influencing mechanisms are not clear so far.. In this study, corn straw was used as an experimental material to determine the mass transfer rules of the physical factors (total moisture and bulk density) and belt conveyor factors (conveying inclination and belt speed) with belt conveyor. For comparison, wheat and sweet sorghum straws were also experimented. The results showed that the mass transfer rate and bulk density of corn straw increased almost linearly along with the increase of total moisture .On the contrary, the dry mass transfer rate decreased linearly. As the bulk density of particle increased with total moisture, the rate of change in mass transfer rate decreased oppositely. In addition, particle size has a vital effect on the mass transfer rate and the fluidization angle of conveyor belt. Decreasing the particle size resulted in an increase of the mass transfer rate, the angle of conveyor belt, and the bulk density in the corn straw experiment. Furthermore, there is a critical belt speed point when conveyor inclination from 25-35°. Once the belt speed surpasses this speed point, an obviously rate of change will be present in the mass transfer rate curve. For the corn straw, the critical belt speed point was 1.6 m/s. Wheat straw and sweet sorghum straw were tested to verify the transfer rules with the same testing methods. The correlation between the mass transfer rate with conveying belt inclination in corn straw is different from that in wheat straw, whose correlation was linear dependence. But the results from straw of sweet sorghum test was similar to that of corn straw. The experimental results lead to the conclusion that the same type bio-structure straw has the same mass transfer law. To the corn and sweet sorghum straw, the conveying inclination should less than 32° and 35.5°, the belt speed should exceed 1.6 m/s and 1.8 m/s respectively. In the mass transfer process stage, critical fluidization angle is an important physical parameter, which has important influences on mass transfer rate. In this paper, the computed correlation function has been shown that fluidization angle equal to the weighed linear relations of the accumulated angle of move, which corresponding to every particle size range. The theoretically calculated results had a good agreement with the experimental results. Above all, this paper provided the research methods for other agriculture residues' mass transfer rate with belt conveyor.