With the rapid development of manufacturing industry, the tool performance is more and more demanding in processing, and the cutting edge passivation technology is the key to improve the tool performance. In this study, a new tool passivation method, namely starch based abrasive flow passivation method, is proposed, which provides a new method for tool edge passivation. Single factor test method was used to passivate carbide end milling cutter by vertical rotation passivation method and starch based abrasive flow passivation method. The test results show that the radius of the cutting edge of the unpassivated tool is the smallest, and there are many defects, and the edge shape is sharp. The radius of cutting edge obtained by vertical rotating passivation method changes little, but the defect of cutting edge still exists, and the blade shape presents uneven blunt circular shape. After starch-based abrasive flow passivation, the edge radius changed the most, some edge defects were removed, and the edge shape showed a uniform blunt circular shape. Therefore, the starch-based abrasive flow passivation method can not only remove the surface defects of the cutting edge better, but also has higher passivation efficiency and the change rate of the cutting edge radius. Considering the needs of tool production, the starch-based abrasive flow passivation method can significantly improve tool performance, reduce tool wear and improve machining quality.