Since　titanium　has　high　afnity　for　hydrogen　and　reacts　reversibly　with　hydrogen,　the　precipitation　of　titanium　hydrides　in　titanium　and　its　alloys　cannot　be　ignored.　Two　most　common　hydride　precipitates　in　α-Ti　matrix　are　γ-hydride　and　δ-hydride,　however　their　mechanisms　for　precipitation　are　still　unclear.　In　the　present　study,　we　find　that　both　γ-hydride　and　δ-hydride　phases　with　different　specific　orientations　were　randomly　precipitated　in　the　as-received　hot　forged　commercially　pure　Ti.　In　addition,　a　large　amount　of　the　titanium　hydrides　can　be　introduced　into　Ti　matrix　with　selective　precipitation　by　using　electrochemical　treatment.　Cs-corrected　scanning　transmission　electron　microscopy　is　used　to　study　the　precipitation　mechanisms　of　the　two　hydrides.　It　is　revealed　that　the　γ-hydride　and　δ-hydride　precipitations　are　both　formed　through　slip　+　shuffle　mechanisms　involving　a　unit　of　two　layers　of　titanium　atoms,　but　the　difference　is　that　the　γ-hydride　is　formed　by　prismatic　slip　corresponding　to　hydrogen　occupying　the　octahedral　sites　of　α-Ti,　while　the　δ-hydride　is　formed　by　basal　slip　corresponding　to　hydrogen　occupying　the　tetrahedral　sites　of　α-Ti.　©　2021