In this paper, the scattering measuring principle of turbidity is introduced firstly. The new type of turbidity sensor probe designed in this paper overcomes the deficiencies of existing technologies, which has higher sensitivity, strong anti-interference and can detect the turbidity accurately and continuously. The system designed with the core of MCU C8051F020 is presented. Then the design of turbidity sensor probe, data acquisition, processing and non-linear compensation are introduced in detail. Besides, in order to eliminate the impact of temperature on the turbidity measurement and improve the measurement accuracy, temperature measurement circuit has been designed. Test results have shown that the designed on-line turbidity-meter has some advantages: low price, high precision, easy operation etc. It can be widely applied in the fields of waterworks, industrial production, aquaculture, environmental protection and so on