esla meter and fluxmeter can both measure the residual magnetic induction intensity of magnets, but when measuring small magnets, the distance between the probe and the surface of the sample must be removed accurately when measuring with Hall probe (Tesla meter), otherwise the measurement error is very large. The Helmholtz coil and fluxmeter are used to effectively solve this problem. Helmholtz coil is used to generate a uniform magnetic field, otherwise, it can also be used for open-circuit sample magnetic flux measurement. Moving the tested magnet out of the coil center, the magnetic flux in Helmholtz coil changes to induce voltage and transmits it to fluxmeter. fluxmeter obtains the change of magnetic flux through data processing. Magnetic flux coils can be customized according to coil constants of different types of fluxmeter.