Abstract: In order to address increasing severe water pollution issues，as well as allowing relative technician better knowreal time water parameters information，a water monitor system was put forward，which was developed base on Python Flask，a microframework for website and apply grey model theory，a water parameters early warning model was established.System was able to collect real time water parameters′ data via wireless sensor network，then upload collected data into OneNet cloud.Web system was deployed on a local server，programed to access the cloud periodically，with the propose of downloading cloud data to do initial treatment and store it into local database.All these processes were transparent to users.Users could access the data by accessing system′s website，according to users′ option，system will extract relevant data from its database，then applying grey model to run early warning algorithm，so that the system could calculate water parameters′ short-middle term variation trend，and demonstrate to users in diagram，if predicting data was out of safety range，system would automatic send a warning e-mail to users，make sure that users could better prepare for potential risks.After several days of field testing，result showed that system could operate properly，demonstrate high practical value.