Aiming at the problems of small effective area, fixed position and cumbersome arrangement of the traditional velocimetry device in the field of area-intercept velocimetry, based on the principle of electromagnetic induction, a new type of electromagnetic induction sensing unit is proposed and verified for the accurate measurement of the initial velocity of the projectile. Compared with the traditional magnetic induction coil, this structure adopts an induction coil wrapped with a permanent magnet, so that the projectile does not need to be magnetised to generate an induced electromotive force, which improves the sensitivity and measurement accuracy of the velocimetry target. In addition, the sensing unit is independently arranged coaxially with the trajectory, which effectively solves the problem of the relative position between the direction of the ballistic trajectory and the stable position of the test device, increases the effective area of the magnetic induction, and strengthens the portability of the measurement device, which can make it Flexible use in a variety of projectile velocity measurement occasions. The solution uses COMSOL software to model the sensing unit, and conducts detailed simulation analysis of the permanent magnet model and the dynamic process of the projectile passing through the magnetic field under different conditions. Based on the simulation data to create a coil sensing unit, and the simulation results of a number of experimental verification, test results show that the sensing unit sensing voltage increases with the speed of the projectile, and the two are linear within a certain range, consistent with the results obtained from the simulation. This study not only provides theoretical basis and data support for the optimisation of electromagnetic induction velocity target, but also outlines an effective solution for the measurement of in-bore and out-of-bore ballistic muzzle velocity of electromagnetic artillery and other high-speed launch systems.