The　study　focused　on　the　development　and　the　status　quo　of　modern　urban　water　system　using　the　scientific　method　at　the　ecological　standpoint,　and　discussed　the　root　of　water　crisis　and　resource　depletion.　It　put　forward　the　concepts　of　recycling　urban　water　system　and　habitat　ecological　sanitation　system　based　on　microbiology　and　ecology,　which　was　the　only　way　to　alleviate　the　crisis　in　water　and　resource,　to　sustainable　survival　and　development　of　human　society,　and　the　basis　of　recycling　city.