Abstract: Aiming at the problems that the existing water quality monitoring instrument measurement parameters are relatively single,poor real-time,low accuracy of measurement degree,a multi-parameter water quality real-time monitor instrument was designed based on ARM+FPGA.Adopting the method of multiplexed signal acquisition and storage on water quality.This instrument used the parallel working mode of FPGA to conduct,and processed by the ARM processor.The experimental results showed that:the water quality monitor parameters had high measurement accuracy,good real-time,stable and reliable performance,the measurement indexes could meet the design requirements.