All-dielectric waveguide modulators nowadays are critical for on-chip photonic circuit’s integration. We propose and theoretically demonstrate a graphene-based all-dielectric waveguide modulator with offset nanowires. The displacement between the nanowires causes the electric field parallel to the graphene to increase, thereby realizing an enhanced field modulation effect. We obtain the best modulation performance by optimizing the structural parameters and changing the offset distance of the nanowires. Analysis of the simulation results indicate that the structure offers a high modulation depth (>0.13  dB  /  μm) covering the S  ,  C, and L bands. Benefitting from the strong subwavelength confinement and excellent broadband modulation performance, the proposed optical waveguide modulators offer a significant potential to realize various long-wave integrated modulators, interconnects, and optoelectronic devices.