An　accurate　analysis　of　casing　stress　distribution　and　its　variation　regularities　present　several　challenges　during　hydraulic　fracturing　of　shale　gas　wells.　In　this　paper,　a　new　analytical　mechanical-thermal　coupling　method　was　provided　to　evaluate　casing　stress.　For　this　new　method,　the　casing,　cement　sheath,　and　formation　(CCF)　system　was　divided　into　three　parts　such　as　initial　stress　field,　wellbore　disturbance　field,　and　thermal　stress　field　to　simulate　the　processes　of　drilling,　casing,　cementing,　and　fracturing.　The　analytical　results　reached　a　good　agreement　with　a　numerical　approach　and　were　in-line　with　the　actual　boundary　condition　of　shale　gas　wells.　Based　on　this　new　model,　the　parametric　sensitivity　analyses　of　casing　stress　such　as　mechanical　and　geometry　properties,　operation　parameters,　and　geostress　were　conducted　during　multifracturing.　Conclusions　were　drawn　from　the　comparison　between　new　and　existing　models.　The　results　indicated　that　the　existing　model　underestimated　casing　stress　under　the　conditions　of　the　geostress　heterogeneity　index　at　the　range　of　0.5-2.25,　the　fracturing　pressure　larger　than　25MPa,　and　a　formation　with　large　elastic　modulus　or　small　Poisson＇s　ratio.　The　casing　stress　increased　dramatically　with　the　increase　of　in　situ　stress　nonuniformity　degree.　The　stress　decreased　first　and　then　increased　with　the　increase　of　fracturing　pressure.　Thicker　casing,　higher　fluid　temperature,　and　cement　sheath　with　small　modulus,　large　Poisson＇s　ratio,　and　thinner　wall　were　effective　to　decrease　the　casing　stress.　This　new　method　was　able　to　accurately　predict　casing　stress,　which　can　become　an　alternative　approach　of　casing　integrity　evaluation　for　shale　gas　wells.