Fused silica with hard and brittle characteristics offers poor machinability due to its low fracture toughness. Conventional grinding (CG) inevitably produces severe subsurface damage and low material removal rates. Laser-assisted machining (LAM) technology facilitates the improvement of the machinability of fused silica. However, the dynamic removal behavior of fused silica under laser heating remains ambiguous. In this study, a molecular dynamics (MD) model for single-abrasive laser-assisted grinding (LAG) of fused silica is constructed. The microscopic tribological mechanisms under various laser powers are systematically investigated, including the surface formation, densification behavior, grinding forces, and subsurface stress state and deformation. The results indicate that laser heating leads to a transition of the removal mechanism from densification to shear flow. In addition, LAG contributes to the reduction of grinding forces, which can be attributed to two aspects. One is that laser heating promotes the thermal motions of fused silica atoms and thus degrades the stability of the crystal structure, and the other is that laser heating induces larger atomic voids in the area to be removed and thus minimizes the hindrance to the motion of abrasive. Furthermore, LAG alleviates the stress concentration phenomenon and lessens the probability of microcracks. Ultimately, this study proposes a new strategy to quantify the evolution of subsurface damage by means of an index of subsurface deformation depth, and 64 μW is identified as the optimal laser power. In summary, the LAG technology reduces subsurface damage while increasing the removal rate of fused silica. This study provides a meaningful guide for the high-efficient and low-damage processing of fused silica.