MgAlON transparent ceramics have excellent optical and mechanical properties, and have potential applications in both military and civilian fields. In this study, the hot pressing and hot isostatic pressing techniques have been introduced into the fabrication and processing of MgAlON transparent ceramics. The BN material was used to solve the problem of carbon contamination during hot pressing sintering. Mg0.27Al2.58O3.73N0.27 transparent ceramics with good optical properties were obtained. The in-line transmittance, Vickers hardness, fracture toughness and room temperature flexural strength were also characterized. Using BN to wrap the sample effectively eliminates the carbon contamination during high-temperature sintering, and the in-line transmittance of Mg0.27Al2.58O3.73N0.27 transparent ceramics at 650 nm increases from 36.51% to 73.74%. Compared with pressureless sintering, hot pressing combined with hot isostatic pressing sintered Mg0.27Al2.58O3.73N0.27 transparent ceramics have better mechanical properties, with flexural strength of 387.12 MPa, fracture toughness of (3.31±0.20) MPa·m1/2 and hardness of (15.3±0.7) GPa. The research can provide an important reference for improving the performance and technical preparation of MgAlON transparent ceramics.