The　microstructures　and　mechanical　properties　of　the　high　temperature　titanium　alloys　containing　Er,　i.e.　Ti-6Al-2.5Sn-4Zr-0.3Mo-1Nb-0.35Si-xEr　(x=0,　0.1,　0.3wt%),　were　investigated.　Both　the　grain　size　and　lamellar　structure　inside　grains　were　significantly　refined　with　the　addition　of　Er　in　as-cast　alloys.　Lamellar　and　duplex　microstructures　were　obtained　after　forging　and　heat　treatment.　Silicide　precipitates　were　generated　in　the　boundary　of　lamellar　α　phase　after　aging　treatment.　Meanwhile,　a　few　α2　phase　were　precipitated　in　the　alloys　after　aging　treatment.　After　600°C/100h　thermal　exposure,　the　α2　phases　with　a　mean　size　of　7nm　and　spacing　of　10　nm　were　precipitated　homogeneously　in　a　lamellar.　The　creep　properties　were　significantly　improved　by　the　addition　of　rare　earth　Er　due　to　the　formation　of　the　second　phase　containing　Er,　silicide　and　α2　phase.　©　2017　Trans　Tech　Publications,　Switzerland.