β-sialon·TiN composite was fabricated by hot-pressing of a spray-dryed mixture of Si3N4 powder, Ti(Oi-Pr)4 and Al(Oi-Pr)3/n-C6H14 solution. Flexural strength, KIC, phase composition, and microstructure were investigated. Phases identified by XRD in sintered body were β-sialon, O′ sialon and TiN. Reaction of TiO2 with Si3N4 yielded TiN and increased amount of O′ sialon compared with samples without Ti(Oi-Pr)4. The room temperature strength by 3-point bending test was 890MN/m2, lower than that (150MN/m2) of β-sialon which was made from Si3N4 powder and Al(Oi-Pr)3 solution without Ti(Oi-Pr)4, but higther than that (740MN/m2) of β-sialon·TiN made from Si3N4, Al2O3 and TiO2 powders. The inproved strength is due to the finer and more homogeneous microstructure. The lower strength compared with β-sialon without Ti(Oi-Pr)4 was ascribed to the rough surface formed by heat-treatment in air. The Vickers hardness of β-sialon·TiN was about 17GN/m2 and the KIC was about 4MNm-3/2, both slightly higher than those of β-sialon without Ti(Oi-Pr)4. The improvement is probably due to the existence of TiN grains.