Fully densified titanium with ultrafine-grains was fabricated by the sequence of pressing and vacuum sintering followed with a hot isostatic pressing (HIP) with superfine TiH₂ powders as raw material. Then, the influence of the addition of 0.3 mass %Y on the fabrication process and properties of titanium was investigated. Simultaneously, the microstructure, mechanical properties and tensile fractured surface of titanium were systematically evaluated and analyzed. Results shows that, during heating in vacuum sintering process, the Ti powders decomposed from TiH₂ powders were born with outstanding sintering activity. For example, the rapid densification took place at 600~900℃during the sintering process, samples with relative density higher than 97% could be obtained by 2-hour sintering above 1000℃. Noticed that the grain size of the sintered titanium increased when sintering temperature rose, however its average grain size could still remain less than 10 mm when it sintered below 1150℃. The tensile strength was in the range of 700~1032 MPa for the HIP treated Ti without yttrium, while, 750 MPa or higher along with an elongation among 8%~10% for those with addition of 0.3% Y. It is considered that the mechanism of making fine and ultrafine grain titanium from superfine TiH₂ powders could come down to that: Firstly, decomposition of superfine TiH₂ powders granted the newly produced Ti powders with ultrafine initial grain size by inheritance. Secondly, the solid dissolved H atoms, which released during decomposition, in the Ti powders could segregate at crystal defects and thus play a role as an impediment to grain growth during sintering process.