Fully mechanized top coal caving mining was a stoping technology with high yield and efficiency, large-scale, reliability of equipment was premise of normal production. But, under the large mining height and high ground press conditions, when the support top beam of working face middle section and the key section of cover beam cracked, without supporting roof effectively. Based on this problem, Jiulong Mine of Fengfeng Group was taken as an example, the actual site was analyzed, comparing to economic and technical indexes and the construction technology, etc, the reasonable method to resolve the wreck support was settled, through fully mechanized caving roof control, support through the conveyor measures, timely and reasonable frame and other key links, ensured the safe production.