Abstract: In order to obtain water insulation performances of rock strata in Nalinhe No.2 Mine of Mengshaan Mining Area, based on the following geological conditi ons, including deep depth seam, main mining seam threatened by many aquifers and above the thin mudstone insulated layer, the statistical analysis and a lab experim ent method were applied to study the lithology combined features, rock mechanics strength, hydraulic properties and full stress-strain permeability of the overburden str ata above No.3-1 seam.The type of the overburden strata above No.3-1 seam was determined and the comprehensive water insulation performances were evaluated.Th e results showed that the overburden strata above No.3-1 seam mainly was sandstone with a good permeability.A mudstone was a no-swelling and no-disintegration mu dstone with high water stability.After cracking and pressurized by the mining operation, the water insulation of the overburden would be recovered easily and the water i nsulation performances would be poor. Generally, the overburden belonged to medium hardness and hard strata which the comprehensive water insulated performances was common.