Abstract: The annular Al₂O₃–B₄C thin wall tube with the wall thickness of near 0.7 mm was successfully sintered by powder injection molding combined with the solvent degreasing and thermal degreasing, using the multi-component wax-based binder. The results show that, when the paraffin mass fraction is 45%, the feedstock has the lower viscosity and the better bending strength. When the solid phase volume fraction is 58%, the feedstock has the good performance in the premise of low viscosity. When the sintering temperature is in the range of 1550 ℃ to 1650 ℃, the relative density and the bending strength of the pellets increase with the increase of temperature. When the sintering temperature reaches 1650 ℃, the density and strength of the pellets begin to decrease slightly, the density increases with the increase of the B₄C particle size, and the bending strength increases first and then decreases with the increase of particle size.