Traditional rotary tiller (TR), straw rotary burying and returning machine (SR) and subsoiling combine straw rotary burying and returning machine (SSR) were simulated by discrete element method and compared with field experiments. The spatial coordinate of straw in soil was measured by the developed measuring device of straw three-dimensional coordinate, and the spatial state of straw in soil was restored in the three-dimensional drawing software. The straw was quantified and visualized in the three-dimensional drawing. The uniformity of vertical and horizontal distribution of straw in soil were studied by layer, horizontal and vertical division of sampling cubes. The corresponding simulation models were established in the discrete element software, and the same operation parameters were set up with the field experiment. After the simulation work was completed, the amount of straw in the area were calculated by setting different Geometry Bins. They corresponded to the actual field operation of the layer, horizontal and vertical division. The results showed that in the layer process, both the simulated and measured values, the amount of straw buried in the soil by SR and SSR was significantly larger than those of TR, especially in the lower layer of soil, which was several times as much as that of TR. In the layer treatment, the variation coefficients of the simulation and measurement of straw proportion in different layers after TR, SR and SSR operations showed a decreasing trend, and the variation coefficients of SSR were the smallest, which were 28.8% and 28.7%, respectively. The variation coefficients between simulated values and measured values under three kinds of tillage equipment were not very different, with an average error of 9.6%. There was no absolute regular of variation coefficients between simulated and measured values of straw proportion of TR, SR and SSR in the landscape orientation and portrait division, but the variation coefficients of SSR were the smallest in the whole, which showed that the uniformity of vertical and horizontal distribution of straw in soil was the best after SSR straw incorporation, whether in discrete element simulation or field experiment. On the whole, the discrete element simulation fitted the spatial distribution of straw well after field operation, and the relative error was within acceptable range.