Provided are a magneto vibration descaling and scale preventing device of a magnetic conduction flow conveying pipe and an excitation frequency calculating method. The device comprises a single-chip microcomputer main control panel, an LED display control module, a liquid crystal display screen alarm module, a keyboard input module, a work mode adjusting module, a coil power real-time monitoring module, a power supply module, a power amplification module and power coil. According to the characteristic that the straight flow conveying pipe made of a ferro magnetic material conducts magneto high-frequency vibration under the excitation of an alternating electromagnetic field and the linear relation between the vibration frequency of the flow conveying pipe and excitation frequency, the resonant frequency of the flow conveying pipe is obtained by calculating the vibration equation of the flow conveying pipe, so that the flow conveying pipe vibrates at an inherent frequency state, and then scale and other dirt in the pipe wall are made to fall off and be taken away by running water through high-frequency vibration. The magneto vibration descaling and scale preventing device of the magnetic conduction flow conveying pipe and the excitation frequency calculating method have the beneficial effects of saving energy, being environment-friendly, safe, reliable and high in controllability and the like.