In　this　paper,　the　prediction　model　of　rust　expansion　time　of　concrete　structures　with　the　consideration　of　initial　defects　is　established　based　on　the　theory　of　fracture　mechanics.　The　limit　state　function　of　structure　life　prediction　is　established　and　an　analysis　method　of　time-dependent　reliability　based　on　three-order　moment　method　is　developed.　The　results　show　that　compared　with　Monte-Carlo　method,　this　method　reduces　the　calculation　time　and　improves　the　analysis　efficiency　when　the　calculated　results　are　more　consistent　with　each　other.　Among　the　parameters　of　concrete　materials,　the　failure　probability　of　concrete　structure　is　the　most　sensitive　to　the　randomness　and　uncertainty　of　cover　thickness　and　less　sensitive　to　the　probability　distribution　type　of　random　variables.　©　2020,　Shanghai　Jiao　Tong　University　Press.　All　right　reserved.