To address the current problem that the speed of high-speed spinning bodies varies widely and it is difficult to achieve effective speed measurements throughout the entire flight, this article proposes a real-time online rotational speed measurement method based on geomagnetic time domain scalar normalization data. First, the geomagnetic motion characteristics of the body flying under high-speed spinning conditions are investigated. The initial normalized value is determined based on the data received in the initial time window, and then, the initial rotational speed is calculated. Subsequently, the rotational speed derived from the previous moment is used to calculate the length of the next time window, and the received data are dynamically normalized within the time window. Finally, the zero moment in the geomagnetic normalized data curve is obtained, the rotational speed is calculated based on the obtained zero point, and the next time window length is determined. The received geomagnetic information is continuously solved by continuously updating the range of the time window and calculating the calculation mode of the rotational speed within the time window. The simulation results indicate that the difference between the calculated rotational speed and simulated true value is up to 4.57%, suggesting that effective measurement of the rotational speed of high-speed spinning bodies throughout the flight can be achieved. © 2024 IEEE.