GPRS technology is applied to the water quality on-line monitoring system for real-time monitoring of some necessary parameters of water. Sensor signals are processed by ARM9 processor S3C2410

then encapsulated into TCP/IP data packs by GPRS module MC55. Through GPRS accessing the internet

these data packs are transmitted to monitoring center. The system hardware and software design are introduced. System is tested based on some water quality parameters monitoring experiment. Test results show that the system is able to monitor parameter and transmit data stably.