The　influence　of　partial　substitution　of　Hf　for　Zr　on　the　microstructure　and　thermal　stability　of　near-alpha　high-temperature　titanium　alloys　is　systematically　investigated.　The　results　show　that　the　addition　of　Hf　promotes　the　refinement　of　precipitated　phases　of　the　silicides　and　alpha(2)　phase　and　the　(Ti,Zr,Hf)(6)(Si,Sn)(3)　S-2-type　silicides　were　formed　in　alloys　after　aging　treatment.　During　thermal　exposure,　both　silicides　and　alpha(2)　phase　in　alloy　with　2.5　wt%　Hf　exhibited　excellent　anti-coarsening　ability,　which　may　be　attributed　to　the　slow　diffusion　of　Hf　in　Ti　that　significantly　inhibited　the　growth　rate　of　the　precipitated　phase.　The　loss　of　plasticity　of　near-alpha　titanium　alloys　after　thermal　exposure　is　mainly　due　to　the　precipitation　and　coarsening　of　silicides　and　alpha(2)　phase,　therefore,　the　Hf-containing　titanium　alloy　has　more　excellent　thermal　stability,　i.e.,　the　plasticity　loss　rate　is　decreased　from　34.8%　(the　alloy　without　Hf)　to　7.4%　(the　alloy　with　2.5　wt%　Hf).