Abstract: Objective With the increasing demand for lightweight materials, the reliable joining between carbon fiber reinforced thermoplastics (CFRTP) and aluminum alloys has become a research hotspot. This paper aims to research influence of interlayer on microstructure of CFRTP/Al laser welded joint. Methods Laser welding experiments of CFRTP and Al alloy were conducted using 0.1 mm thick Cu, as well as 0.01、0.03and 0.05 mm thick Ti as interlayers. By establishing a FEM of the laser welding process, the temperature field was simulated, analyzed, and subsequently compared with the experimental results. Results The results indicate that with a 0.03 mm thick Ti interlayer, the heat is optimally concentrated in the interfacial region, facilitating reliable joining between the two materials. The welding interface obtained with this 0.03 mm thick Ti interlayer is continuous and features a continuous diffusion layer, yielding a maximum shear strength of 76 MPa for the CFRTP/Al laser welded joint. Conclusion The finite element model can effectively predict the temperature field distribution of welded joints, and the simulation results are consistent with experimental data. It can provide theoretical guidance for optimizing welding parameters and lay the foundation for achieving high-quality welding between CFRTP/Al alloys.