Abstract:With the development of urban economy, the water environment of the city river is seriously polluted and destroyed, and the pH of the water quality is an important indicator of the water pollution. Because of the uncertainty of the water pollution in the city river, a set of real-time detection system for the multi node and multi range of the river urban pH is becoming a requirement under the condition of the field unattended. Each detection node connected with a pH sensor, collects data and transmits to the system base station through the Zigbee wireless module, and the base station stores the each node data with its position information and time information to the cloud database. Managers can use the web site to kown the current situation of the water quality of the every region, if the river is polluted, managers can also be aware of the diffusion of water pollution and pollution sources through the data informations, take measures to reduce the loss in time. Compared with the traditional method of artificial field sampling and laboratory analysis, the application of the system not only greatly improve the early warning ability but also reduce the cost of manpower.