The joining of FeCrAl alloy and Carbon Fiber Reinforced Thermoplastic Composites (CFRTP) presents a promising strategy for the development of lightweight and structurally reliable components. In this study, ultrasonic welding, noted for its efficiency and environmentally sustainable characteristics, was employed to examine systematically examine the impact of surface texturing on joint performance. Two distinct categories of FeCrAl surface textures, discrete unit patterns and continuous groove structures, were created and subsequently welded with Short Carbon Fiber Reinforced Polyamide 6 (SCFR-PA6). The wettability of molten SCFR-PA6 on the textured surfaces and the bonding strength of the resulting joints were evaluated, alongside comprehensive analyses of fracture surfaces and interfacial morphologies. The findings indicated that continuous groove textures significantly improved wettability in comparison to discrete unit textures. Notably, joints with continuous grid-like texturing exhibited complete resin infiltration and achieved the highest bonding strength of 18.26 MPa. This enhancement is primarily attributed to the continuous groove structures, which facilitate unobstructed resin flow and promote the effective extrusion of carbon fibers. A novel reinforcement strategy for metal/CFRTP joints is proposed, wherein interfacial texture design is used to regulate temperature distribution and resin flow dynamics during welding. These results offer critical insights into the optimization of metal/CFRTP joint design and manufacturing processes for advanced structural applications.