Abstract: Seismic arrival time data from broadband arrays deployed along the Longmenshan fault zone were used to invert three-dimensional fine structure models of V_P, V_S, and V_P/V_S at depths less than 24 km and earthquake relocation in the Longmenshan fault zone using the consistency-constrained double-difference tomography method. The results are as follows: (1) The Longmen Shan fault zone exhibits a high-velocity zone between the Beichuan-Yingxiu fault and the Maoxian-Wenchuan fault zone. Within the depth range of 0-8 km, this high-velocity zone is confined beneath the Longmen Shan fault zone. Between depths of 8-20 km, the high-velocity zone merges with the high-velocity zone associated with the Maoxian-Wenchuan ductile shear zone. At depths ranging from 20-24 km, the high-velocity zone becomes concentrated in the central segment of the Longmen Shan fault zone. The Western Sichuan foreland extensional deformation belt on the southeastern side of the Anxian-Guanxian fault maintains consistently low velocities. (2) Earthquakes within the Longmenshan fault zone are predominantly concentrated at depths ranging from 4 to 16 km beneath the Beichuan-Yingxiu fault zone. Seismic activity shows a significant correlation with transitional zones, which signifies shifts between high and low seismic wave velocities as well as regions characterized by elevated velocity ratios. The dip angles of the seismic distribution and velocity anomalies vary across the southern, central, and northern segments of the Longmenshan fault zone. In the northern segment of the Longmenshan fault zone, both high-velocity bodies and earthquakes are concentrated within a depth range of 0-15 km, with an almost vertical dip orientation. (3) The combined analysis of tomographic velocity structures and fracture characteristics in the reflection profiles reveals a Y-shaped hidden fault within the seismogenic zone of the Lushan earthquake. The seismogenic area of the Lushan earthquake is overlain by an aseismic zone layer measuring 10-15 km thick.