On the basis of the experimental device for measuring the moment of ineria of rigid body using thefalling body method , two magnets are installed.The " magnetometer" option in the mobile phone Phyphoxsoftware is used to measure the data of the magnetic field variation over time when the stage rotates.Based onthis data, determine the change in the angle of rotation of the stage over time and caleulate the angularaeceleration of the stage , thereby caleulating the system's moment of inertia.The relative error of the moment ofinertia measured by this method for dise , ring, and eylindrical specimens is less than 19, Through wirelessnetworks , mobile phones and computers can be intereonnected ,and experimental data can be displayed in real-time in the form of charts on the computer desktop,making the experimental process more intuitive.