<p>The size distribution of granular top-coal in LTCC has a great influence on the drawing process, and the spatial motion law of top-coal directly determines the size distribution. To reveal the size distribution characteristics and spatial motion law of top-coal in LTCC panels, first, three top-coal size distribution measurement methods are proposed, and the advantages and disadvantages of each method are compared and analyzed. Then, PFC^3D is used to simulate the complete top-coal drawing process from the original position to the drawing opening, and finally to the rear armoured face conveyor (AFC). The measurement parameters of the size distribution, the distribution law of the drawn top-coal, and its motion trace are analyzed. The results show that the length distribution of drawn top-coal and the volume of drawing body increase approximately in the form of a quadratic function with an increase in the drawing height. The measurement location and length of the size distribution on the rear AFC and belt conveyor are determined. Additionally, the relationships between the top-coal size distribution and measurement length on the rear AFC and belt conveyor are quantified. Furthermore, the upper top-coal is observed to mainly concentrate on the rear AFC near the support side, and alternating circulation is evident on the belt conveyor. Based on the field measurement data, the variation characteristics of the top-coal size distribution under different coal seam conditions are analyzed. The research results can provide a new approach for accurate calculation of the top-coal size distribution in the field and lay a data foundation for spatial motion law of top-coal.</p>