Abstract: Magnetic drum coating material was prepared by using the magnetic slurry inunction process and the influence of component on the property of coating material was investigated. A high-performance magnetic drum whose diameter is 30-40 mm was ultimately manufactured with this material. The magnetic drum was magnetized and recorded 128 and 256 magnetic poles. A metal film magnetoresistance transducer was used to detect the distributing magnetic field of the drum surface and the signal was transformed to an oscillograph and an arithmometer by a magnifying and plastic circuit. It is shown that the output signal waveform is fine and the count is integrated.