Urban　river　network　plays　an　important　role　in　the　process　of　drainage.　The　real-time　prediction　system　of　river　water　level　can　provide　early　warning　information　to　the　decision-makers　of　relevant　departments　in　time,　which　plays　an　important　role　in　reducing　flood　risk.　Aiming　at　the　rapid　and　strong　response　of　urban　river　to　rainfall,　a　real-time　rolling　prediction　system　of　urban　river　water　level　is　proposed　based　on　radar　rainfall　prediction　products　and　coupling　model　of　hydrology　and　hydrodynamics.　In　the　system,　each　simulation　is　divided　into　two　parts:　the　review　period　and　the　prediction　period.　In　the　review　period,　the　river　model　is　driven　by　the　observed　rainfall　to　obtain　the　latest　simulation　state　to　avoid　cumulative　error,　while　in　the　prediction　period,　the　radar　rainfall　is　used　to　drive　in　the　short-term　prediction　of　river　water　level.　Taking　Fuzhou　as　the　research　area,　a　long　series　review　of　the　process　from　April　1,　2020　to　October　1,　2020　was　carried　out.　The　accuracy　of　the　river　model,　radar-rainfall　and　prediction　system　during　the　study　period　are　evaluated　and　discussed　in　detail.　The　results　show　that　the　river　model　can　simulate　the　process　of　water　level　change　in　rainfall　and　rain　free　period.　The　performance　of　radar　rainfall　to　total　rainfall　prediction　is　better　than　that　of　process　prediction.　The　real-time　prediction　system　can　give　the　water　level　risk　according　to　each　radar　forecast　rainfall　process,　and　has　good　performance　in　judging　the　peak　water　level　and　peak　time,　which　can　provide　reference　for　urban　river　dispatching　decision-makers.