Thermohydrogen processing can enhance workability,decrease flow stress and deforming temperature of titanium alloys.In this study,thermohydrogen processing was carried out for metastable β-type TB8 alloy.The microstructures of hydrogenated TB8 alloy were investigated based on scanning electron microscopy (SEM),transmission electronic microscopy (TEM) as well as X-ray diffraction (XRD) analysis.The results reveal that δ hydride phase forms in the hydrogenated TB8 alloy,but the amount of β phase increases with hydrogen content increasing.Single β phase appears when the hydrogen content reaches 0.7 wt％.The alloying elements redistribute in the hydrogenated TB8 alloy,and hydrogen leads to the reduction of the alloying elements in β phase.The room-temperature compression tests were performed on a MTS809 machine.It is found that the room-temperature yield strength of hydrogenated TB8 alloy decreases.And minimum yield strength is obtained at a hydrogen content of 0.5 wt％.The ductility does not decrease within 0.7 wt％ hydrogen content.These results provide theoretical basis for improving the formability and promoting the applications of TB8 alloy.