By　deploying　the　ubiquitous　and　reliable　coverage　of　low　Earth　orbit(LEO)satellite　networks　using　optical　inter　satel-lite　link(OISL),computation　offloading　services　can　be　provided　for　any　users　without　proximal　servers,while　the　resource　limita-tion　of　both　computation　and　storage　on　satellites　is　the　impor-tant　factor　affecting　the　maximum　task　completion　time.In　this　paper,we　study　a　delay-optimal　multi-satellite　collaborative　computation　offloading　scheme　that　allows　satellites　to　actively　migrate　tasks　among　themselves　by　employing　the　high-speed　OISLs,such　that　tasks　with　long　queuing　delay　will　be　served　as　quickly　as　possible　by　utilizing　idle　computation　resources　in　the　neighborhood.To　satisfy　the　delay　requirement　of　delay-sensi-tive　task,we　first　propose　a　deadline-aware　task　scheduling　scheme　in　which　a　priority　model　is　constructed　to　sort　the　order　of　tasks　being　served　based　on　its　deadline,and　then　a　delay-optimal　collaborative　offloading　scheme　is　derived　such　that　the　tasks　which　cannot　be　completed　locally　can　be　migrated　to　other　idle　satellites.Simulation　results　demonstrate　the　effective-ness　of　our　multi-satellite　collaborative　computation　offloading　strategy　in　reducing　task　complement　time　and　improving　resource　utilization　of　the　LEO　satellite　network.