Abstract: The experimental study was made by the shaking-sieving measure for the evaluation of roughage particle-size distribution. In the practical experiment, four sets of practicable sieves were studied. The absolute deviation was put forward for evaluation of particle-distribution precision in the paper. By the experimental study,the optimum set of sieves—square-case punched sieves was selected, and the optimal parameters were obtained by the experiment: loading coefficient 0.4～0.6, sieving duration 2～5 min.