In order to improve the timeliness and measurement precision of water quality monitoring in aquaculture, a water quality parameter monitoring system based on wireless sensor network is designed. The system is made up of water quality parameter acquisition terminal, distributed sensor network, transmission control center base station and remote online monitoring system. The parameter acquisition terminal acquires water quality parameters and transmits them to the center base station, and then sends them to the remote online monitoring center via GPRA to realize adjustment of water temperature, pH and dissolved oxygen (DO) according to the parameters input by the user to the monitoring center. The digital filtering algorithm is introduced during parameter measurement to improve measurement precision, and PID controller set by improved particle swarm optimization (PSO) is used to adjust the water quality parameters. The results show that the measurement precision is up to standard, the measurement error of temperature, pH and DO is 2.1%, 1.3% and 3.6% respectively, and the maximum error of the system to temperature, pH and DO is 1.9%, 2.6% and 3.1% respectively. The system operation is stable and reliable.