Abstract: In order to solve the problem that casing milling and fishing technology is used to salvage directional borehole in coal mine after the occurrence of stuck drilling accident in mudstone stratum, the hole with large rotary resistance of casing milling drilling pipe and hole shrinkage or collapse, even cause the risk of secondary stuck drilling, through analyzing the difficulties of milling and fishing technique in mudstone formation, learn from oil and geology industry mudstone formation drilling construction technology, the technique of short hole sweeping is proposed, and the interval is about 15 m. At the same time, based on the short hole sweeping, the milling and reaming techniques of all-hole sleeve and partial eccentric sleeve are proposed. With these techniques, the accident of stuck in the top plate of Xin’an Coal Mine with the hole depth of 465 m was solved successfully, and of which 345 m to 450 m are mudstone, this depth created the hole depth record of successfully milling and fishing the rock hole.