Gliding arc discharge (GAD) holds significant potential for energy and environmental applications, particularly in biomass tar reforming. In this study, we developed two GAD reactors coupled with a magnetic field for biomass tar reforming. The reactors were designed with two different configurations by varying the magnetic field direction relative to the electrodes: magnetically accelerated gliding arc discharge (MAGAD) and magnetically stabilized gliding arc discharge (MSGAD). The reforming performance and discharge characteristics of these two configurations were systematically evaluated and compared with those of a normal GAD (NGAD). MAGAD demonstrated superior reforming performance, achieving the highest conversion for toluene (71.4 %) and phenol (87.5 %), as well as the highest yields of H2 (22.4 %) and C2H2 (12.6 %) at a magnetic field intensity of 133 mT. In contrast, MSGAD achieved the highest energy yield (47.1 g/kWh) but exhibited lower tar conversion due to reduced discharge power. In the MAGAD system, the magnetic field generates a synergistic effect between the Lorenz force and gas thrust, accelerating and elongating the arc along the electrodes. This results in increased discharge power and frequency, as well as an expanded discharge region. This leads to the generation of more reactive species, which enhances the breakdown of benzene rings into short-chain hydrocarbons and reduces the formation of liquid byproducts. These findings demonstrate the potential of manipulating magnetic fields to optimize GAD systems for efficient biomass tar reforming, offering a promising strategy to improve the performance of plasma-based chemical reactions.