According to the actual needs of aquaculture water quality monitoring and regulation, a water quality monitoring and regulation system is proposed based on narrow-band Internet of things (NB-IoT) and unmanned ship inspection technology. The unmanned ship is used as a mobile water quality sensing node to collect aquaculture water quality information, and then uploads the data to the OneNET cloud platform through NB-IoT wireless communication technology, and finally the water quality information is visualized on the web interface of the terminal. At the same time, a water quality adjustment node with water quality adjustment equipment as the core is designed, and the control instructions issued by the terminal are received through the NB-IoT wireless communication module to complete the adjustment of the water quality equipment. The experimental results show that the unmanned ship can automatically plan the path according to the user's instructions, and send back the currently measured water temperature, turbidity, nitrate content, ammonia nitrogen content, dissolved oxygen and pH value in real time. Meanwhile, in the web application, water quality data and aquaculture suggestions given by the expert system are  readily accessible, and equipment such as aerators and water exchange pumps can be controlled online to adjust water quality. The research shows that this system meets the needs of multi-point inspection and adjustment of water quality in aquaculture farms, and has considerable application prospects.