In this work, a robust brazed joint of carbon fibre-reinforced carbon-based (C/C) composite and TC4 alloy was produced by utilising a slice of C/C as an interlayer. The C/C slice interlayer caused microstructural and mechanical property enhancement. During brazing, massive in situ formed carbon fibres broke away from the C/C slice bundles and were distributed in a three-dimensional interlocked network. These unique fibres consumed excessive Ti to inhibit the formation of excess brittle Ti-Cu compounds in the brazing seam. This reduced the coefficient of thermal expansion effectively, consequently relieving the high residual stress in the joint interface. The average shear strength of the joint brazed with the C/C slice interlayer reached 1.65 times higher than the directly brazed one.