Based　on　the　flat　shell　theory,　the　program　has　been　developed　to　analyze　the　two-way　reinforced　concrete　slabs　at　ambient　temperature,　and　the　efficiency　of　the　model　was　verified　in　the　analysis.　In　addition,　this　paper　proposed　the　transient　strain　model　of　concrete　with　transient　modulus　under　the　bi-axial　stress　state.　According　to　the　developed　temperature　program,　the　proposed　model　was　used　to　predict　the　fire　behavior　of　two-way　reinforced　concrete　slabs,　and　the　fire　resistance　of　the　slab　based　on　different　criteria　has　been　studied　in　the　paper.　The　results　show　that　the　predictions　agree　well　with　the　experimental　results,　and　demonstrate　the　validity　of　the　transient　strain　model.　Compared　with　other　criteria,　the　fire　resistance　value　based　on　the　temperature　criterion　is　relatively　conservative.