Abstract: To enhance the reliability of Al/SiC-SiC heterogeneous material connections between the Al/SiC mirror frame and the SiC main mirror body in space reflector structures, mitigate residual stress, and prevent crack propagation, a small-scale interlocking joint design was employed. This design was analyzed using the ABAQUS finite element simulation software to simulate and calculate the bending stress distribution and stress peaks under different joint structures, quantities, and loading conditions. The results demonstrate that the trapezoidal groove interlocking joint with an aspect ratio of 1 exhibits the lowest simulated bending stress peak of 508 MPa, with no significant stress concentration areas observed in the joint, indicating optimal reliability optimization. This conclusion was further validated through brazing experiments, which revealed that the trapezoidal groove interlocking joint exhibited no apparent defects in its microstructural morphology and achieved a high bending strength of 198 MPa.