The existing experimental results have shown that the magnetic characteristics of amorphous wires with different lengths or of the same amorphous wire at different longitudinal locations are significantly different. To study this effect, the magnetic field at the end of the amorphous wires is obtained by numerical computation method based on the supposed uniform distribution of the magnetic charge. Then, the general formula of the magnetic field inside the amorphous wire is deduced by analyzing the calculation results and using the fitting algorithm. Because the magnetic field intensity inside the wire is restricted by the external magnetic field source, the model of three magnetic zones is proposed, which consists of the zone of uniform magnetic field in the middle of the wire, the magnetic field entrance-zone and exit-zone at the two ends. The critical length of the magnetic end effect can be estimated by a formula derived from the model. The simulation results of the magnetic end effect can satisfactorily explain the existing experiments.