Lost circulation of borehole is one of the complex problems in coal bed drilling process and cement slurry sealing is the most commonly used method on site. However, lost circulation of cement slurry often happens in fissured, cave or high permeability formations. The paper introduced special fiber into the conventional cement slurry systems and made research on its sealing performance, rheopecticity, fluidity and mechanical property of cement stone by laboratory experiments. The paper also analyzed the sealing mechanism of fiber cement slurry and the applications of which were introduced in the drilling and cementing processes. The research results demonstrate that fiber cement slurry has good sealing effect in above-mentioned formations and it has a promising future in coal bed drilling fields.