The invention provides a clamping device for assembling and disassembling a pipeline in a wall body of a combined workshop and a mounting method thereof. The clamping device and the mounting method thereof are particularly suitable for construction of a combined workshop, the efficiency of assembling or disassembling the pipeline in the wall body can be improved, the wall surface treatment procedure can be avoided, and the maintenance cost can be lowered. The clamping device comprises a sleeve, fillers, bolts and nuts, circular-ring sealing plates and the like; the sleeve is of a circular pipe steel structure and is arranged on the wall body; through holes are uniformly formed in the circumferential surfaces at the two ends of the sleeve and are used for installing the circular-ring sealing plates; a gap among the inner wall of the sleeve, the outer wall of the pipeline and the circular-ring sealing plates is filled with the fireproof cotton alumina silicate fibre fillers, and the fillers are used for clamping the pipeline. The clamping device and the mounting method thereof have the advantages that the structure is simple, the use is flexible, the wall body is not damaged and the like, the pipeline maintenance or replacement efficiency can be obviously improved, the labor intensity can be obviously and effectively relieved, the safety of the interlayer work or aloft work can be improved, and the complicated working procedure that the pipeline can be maintained or replaced by excavating the wall body surrounding the pipeline can be avoided.