In order to solve the problem of roof hanging distance too long underground goaf in coal mining face,the field observation,nu-merical simulation and experimental research method were used,the hard roof control technology was proposed based on analyzsis strata be-haviors features of hard roof underground goaf in coal mining face.The analysis results showed that the periodic weighting were 33、40 m of frist rock beam and second rock beam of coal mining face in No.22 coal seam.The dynamic coeficient was 1.8 during first weighting,during the periodic weighting was 1.42~1.65.The UDEC2D numerical simulation software was used to analyze the roof migration situation of No. 3213(1)coal mining face and obtained the different hard roofs fracture condition between appeared,breakage form,dynamic pressure characteristics and abscission layer hard roof underground goaf in coal mining face.By using deep hole blasting of forced caving technology could make the hard rock generated a lot of internal conduction fissure space,this technology could make the first weighting of first rock beam decrease 21.1 m and the second rock beam decrease of first rock beam 27.2 m,effective prevention and control of the roof hanging distance too long was achieved.%为解决采空区下工作面悬顶距离过长的问题，采用了现场观测、数值模拟、试验研究等手段，在分析采空区下坚硬顶板的矿压显现特征的基础上，提出了坚硬顶板控制技术。分析可知二2煤层工作面的第1岩梁、第2岩梁平均周期来压步距分别为33、40 m，初次来压期间支架的动载系数达1.8，周期来压期间为1.42~1.65；利用UDEC2D数值模拟软件，对3213（1）工作面顶板运移情况进行分析可得到采空区下不同坚硬岩层间的裂隙发育情况、破断形式、动压显现特征以及离层情况；通过采用深孔爆破强制放顶技术可使坚硬岩层内部产生了大量的导通裂隙空间，该技术可使第1岩梁的初次来压步距缩短为21.1 m，第2岩梁初来压步距缩短为27.2 m，有效防治了悬顶距离过长的问题。
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