The mud content is one of the important characterization parameters of the quality of the base sand.It affects the quality of castings by its effects on the mold sand，in which base sand is the aggregate. At present， the detection of mud content in base sand is mainly based on the national standard detection method，and the operation process is cumbersome and time-consuming，so it is not suitable for on-site inspection in sand mixing shop. Based on the basic principles of the national standard detection method，uses a turbidity sensor to measure the mud content of the base sand after vortex washing，and develops a rapid detection method and device with short measurement period and high degree of automation. Compared with the national standard detection method，the test time is reduced by 90%. Through T-test，it is proved that the test results are 99% close to those of the national standard.