Purpose　-　The　purpose　of　this　study　is　to　evaluate　the　potential　risks　of　copiright　infringement　in　digital　library　based　on　the　extension　theory.　Design/methodology/approach　-　At　first,　the　analytic　hierarchy　process　(AHP)　is　used　to　determine　the　weights　of　the　existing　indicator　system　for　early　warning.　Second,　a　model　is　built　to　evaluate　the　potential　risks　of　copiright　infringement　based　on　the　extension　theory　in　digital　library.　Finally,　a　real-world　application　is　presented　to　show　the　effectiveness　and　usefulness　of　this　approach.　Findings　-　The　main　findings　of　this　paper　are　as　follows:　the　early　warning　extension　theory　model　is　effective　in　distinguishing　the　degree　of　the　potential　risks　of　copiright　infringement　in　digital　library;　the　ranges　of　the　value　and　the　values　of　the　indicators　can　directly　affect　the　results　while　using　this　approach,　so　the　accuracy　of　these　two　aspects　is　a　crucial　question.　Social　implications　-　The　social　impact　is　that　copiright　infringement　risks　of　digital　library　is　reduced;　the　lawsuit　rate　and　economic　loss　due　to　copiright　infringement　are　thereby　decreased　as　well.　Originality/value　-　This　paper　introduces　the　evaluation　of　the　potential　risks　of　copiright　infringement　based　on　the　extension　theory　in　digital　library.　The　results　provide　support　for　the　decision-makers　in　handling　the　potential　risks　of　copiright　infringement　in　digital　library.　©　2016　Emerald　Group　Publishing　Limited.