This paper mainly describes the design and implementation process of a metal surface cleanliness tester based on ultraviolet fluorescence method.First,it introduces the importance of metal surface cleanliness detection and points out the limitations of existing detection methods.Then,it describes the advantages of ultraviolet fluorescence method in this field and the main characteristics of this product.Then,it explains the detection principle of ultraviolet fluorescence method,and explains the overall design architecture of the tester,covering hardware design(including core circuit design)and software design(including mathematical model establishment method).Finally,by showing specific field application cases,it strongly proves its accuracy and reliability in different metal materials and in the face of different types and degrees of pollution.The tester provides an effective technical means for the rapid and accurate detection of metal surface cleanliness,and has important application value in industrial production,quality control and other related fields.