The　arbitrary　distribution　of　groundwater　monitoring　sites　and　the　redundancy　of　observation　data　restrict　the　ability　of　monitoring　network　to　provide　reliable　and　effective　data　information.　The　purpose　of　this　study　is　aimed　at　finding　a　quantitative　method　to　screen　ideal　monitoring　locations　and　evaluate　the　efficiency　of　the　monitoring　network.　In　terms　of　site　selection,　we　use　hydrogeological　information,　monitoring　density　and　monitoring　location　to　select　the　suitable　site　to　monitor　groundwater　quality,　understand　the　temporal　trends　and　identify　the　abnormal　signals　of　pollution　sources.　To　evaluate　the　efficiency　of　monitoring　network　we　used　the　groundwater　quality　data　for　consecutive　years　to　evaluate　the　groundwater　monitoring　network　based　on　information　entropy　and　principal　component　analysis　(PCA).　The　results　show　that　the　optimized　groundwater　monitoring　network　is　comprised　of　10　monitoring　wells.　The　efficiency　evaluation　results　of　information　entropy　and　PCA　are　basically　consistent.　The　maximum　mutual　information　(T)　and　comprehensive　index　of　monitoring　site　(Laiguangying)　were　1.29　and　3.25　respectively,　while　the　minimum　T　and　comprehensive　index　of　monitoring　site　(Jinzhan)　were　1.05　and-0.36　respectively,　and　the　data　efficiency　was　low.　This　study　provides　a　good　example　for　optimizing　a　groundwater　pollution　monitoring　network.