The　maintenance　policies　based　on　random　working　time　guarantee　the　continuity　of　system　functionality.　This　paper　studies　a　random-time　component　reallocation　and　system　replacement　(RCS)　policy,　in　which　the　random-time　system　replacement　is　to　replace　the　system　at　the　planned　preventive　time　or　the　random　working　time,　whichever　comes　first,　the　random-time　component　reallocation　is　to　balance　the　degradation　of　components　by　reallocating　components　at　random　working　time　before　system　replacement,　and　minimal　repair　is　implemented　for　failed　components.　To　improve　the　efficiency　and　flexibility　of　RCS　policy,　we　first　establish　an　optimization　model　to　minimize　the　expected　system　maintenance　cost　per　unit　time　based　on　a　given　interval　for　random-time　component　reallocation,　and　analytical　results　are　derived　by　comparing　the　proposed　policy　with　the　preventive　component　reallocation　and　random-time　system　replacement　policy,　and　the　simple　random-time　system　replacement　policy.　Next,　we　construct　another　optimization　model　to　maximize　the　interval　length　for　the　random-time　component　reallocation　constrained　by　the　threshold　of　the　efficiency　level　of　RCS　policy.　Numerical　experiments　demonstrate　the　performance　of　the　RCS　policy　and　provide　guidance　for　the　interval　for　the　random-time　component　reallocation.