The in - situ measurement and analysis of support resistance and top - coal movement in fully - mechanized topcoal caving face of a thick coal seam with dirt band had been carried out in some coal mine, the strata behavior and movement law of top - coal were revealed. It was found that comparing with the case without dirt band the periodic weighting distance, median roof moving coefficient and support resistance all increased to different extent because of the influence of dirt band. The analyses results provided basis for reasonably determining the load and the structural type of support and the top - coal caving parameters.