Abstract: Objective CoCrFeNiMn high-entropy alloy (HEA) was used as an interlayer for resistance spot welding of TC4 titanium alloy and AA6061-T6 aluminum alloy, aiming to promote the application of HEA in Al/Ti dissimilar metal welding. Methods Resistance spot welding experiments were conducted on TC4 titanium alloy coated with a laser-cladded CoCrFeNiMn HEA layer and AA6061-T6 aluminum alloy. Microstructure and fracture characteristics of welded joints were analyzed by scanning electron microscopy (SEM) and optical microscopy. Mechanical properties of welded joints were evaluated through tensile testing and Vickers hardness testing at room temperature. Results CoCrFeNiMn HEA exhibited good wettability on the surface of TC4 titanium alloy, forming a bonding zone approximately 80 μm thickness at the interface of Ti/HEA, which prevented the formation of Ti-Al intermetallic compounds (IMCs). As welding current and welding time increased, diameter of weld nugget in welded joints grew, while tensile-shear load of welded joints first increased and then decreased, peaking at 2.1627 kN. A 3 μm thick serrated reaction zone was observed at the interface of Al/HEA. HEA cladding layer exhibited a gradient structure, with larger equiaxed grains and higher Ti content near the titanium side. Ti/HEA interface showed enrichment of Ti, Ni, and Fe elements, with a bonding zone thickness of approximately 90 μm. Conclusion The laser-cladded CoCrFeNiMn HEA served as an interlayer for resistance spot welding of Al/Ti dissimilar metals. Welded joints demonstrated good mechanical performance under appropriate welding current, while excessive welding current led to issues such as splashing and thinning of aluminum plates. Bonding zone formed a stable solid-solution layer instead of conventional Ti-Al IMCs, validating the potential of high-entropy alloys in Al/Ti welding applications.