Globalization　and　the　spread　of　information　have　made　city　networks　more　complex.　The　existing　research　on　city　network　structures　has　usually　focused　on　discussions　of　regional　integration.　With　the　development　of　interconnections　among　cities,　however,　the　characterization　of　city　network　structures　on　a　regional　scale　is　limited　in　the　ability　to　capture　a　network＇s　complexity.　To　improve　this　characterization,　this　study　focused　on　network　structures　at　both　regional　and　local　scales.　Through　the　lens　of　function　and　innovation,　we　characterized　the　city　network　structure　of　the　Economic　Zone　of　the　West　Side　of　the　Taiwan　Strait　through　a　social　network　analysis　and　a　Fast　Unfolding　Community　Detection　algorithm.　We　found　a　significant　imbalance　in　the　innovation　cooperation　among　cities　in　the　region.　When　considering　people　flow,　a　multilevel　spatial　network　structure　had　taken　shape.　Among　cities　with　strong　centrality,　Xiamen,　Fuzhou,　and　Whenzhou　had　a　significant　spillover　effect,　which　meant　the　region　was　depolarizing.　Quanzhou　and　Ganzhou　had　a　significant　siphon　effect,　which　was　unsustainable.　Generally,　urbanization　in　small　and　midsize　cities　was　common.　These　findings　provide　support　for　government　policy　making.　©　2019　by　the　authors.