The　mechanical　properties　of　molybdenum　wires　doped　with　different　contents　of　La2O3　were　investigated　systematically　and　the　interaction　between　La2O3　particles　with　dislocations　in　Mo-La2O3　wires　were　observed　by　SEM　and　TEM.　It　is　shown　that　Mo-La2O3　wires　possess　much　higher　tensile　strength　than　the　pure　Mo.　In　wires　the　dislocation　motion　is　strongly　hindered　by　La2O3　particles,　which　remains　up　to　much　higher　temperature.　Moreover,　a　number　of　prismatic　dislocation　loops　and　hexagonal　dislocation　network　have　been　formed　in　annealed　Mo-La2O3　wires.　The　higher　strength　of　Mo-La2O3　than　the　pure　Mo　is　attributed　to　the　La2O3　particles　dispersion　strengthening　and　dislocation　strengthening.