From　the　systemic　point　of　view,　strategic　network　is　a　complex　system.　Based　on　niche　theory　in　ecology,　this　paper　proposes　the　concept　of　niche　of　enterprise　node　in　strategic　network,　and　tries　to　research　into　the　measuring　model　for　the　breadth　and　overlap　of　node　niche　in　strategic　network.　This　research　shows　that　strategic　network　node　not　only　has　to　choose　appropriate　niche,　but　also　make　right　adjustment　and　optimization　of　the　niche　according　to　their　goals　and　environmental　change.　At　last,　it　promotes　the　evolution　of　strategic　networks.