Abstract: in order to solwe the problem of sot rock roadyway with large c.oss section dffcuto conto,based on the eastic-plasic theory,the ifuence of secionsize of the chamber and the support resistance on the defomation and falre mechanism ofthe surounding ock for the soft rock chamber with a large cross section was analyzed.Then.taking the main shat skip loading chamber of XinshanghaiNo.1Coal Mine in lner Mongolia as the engineering background,the fnie difrence sofware FLAC3 Dwas used to numeically calculate and analyze the deformation law and distribution of plastic zone for the surounding rock of the chanmber under three different supporing schemes on the basis ofthe measurement of rocksrength /oose ciole and the strengthfor the surounding rock.The resuits showed that the comtbined supporting stucture of anchor cables and the geogrd reinforced concreted presents a better ovfall erormance compared with the raditional anchor.and the plastc zone and suriace deformation of the surounding rock reduce signifcantly afer supporting. ndustral'est indicated that th maximum extrusion deformation of the middle chamber was only 5.5 cm,and the surrounding rock stress was very low after the stability of the supporting. Therefore or the chamber were fully insured.