According　to　the　reliability　evaluation　system　of　production　line　and　the　Petri　net　model　of　production　line　availability,　the　relationship　between　reliability　index　and　reliability　index　correlation　is　analyzed　by　statistically　calculating　reliability　data.　According　to　the　relationship　between　the　actual　production　situation　and　the　correlation　between　the　reliability　index　and　the　reliability　index,　the　analytic　hierarchy　process　based　on　interval　judgment　is　used　to　give　the　weight　of　each　reliability　indicator　to　the　reliability　of　the　production　line,　and　according　to　the　reliability　index　The　membership　function　of　the　evaluation　grade　is　evaluated　by　the　fuzzy　comprehensive　evaluation　method　for　the　reliability　of　the　engine　crankshaft　flexible　production　line.　©　Published　under　licence　by　IOP　Publishing　Ltd.