In　this　paper,　crack-free　and　transparent　Gd0.9La0.1VO4　single-crystal　co-doped　with　Yb3+　and　Ho3+　ions　has　been　grown　by　Czochralski　method.　The　absorption　and　emission　spectra　of　the　crystal　were　measured　at　room　temperature.　With　the　absorption　spectrum,　the　intensity　parameters　Q;,　of　Ho　31　ions　were　fitted　based　on　Judd-Ofelt　theory,　which　are　Omega(2)　=　7.87　x　10(-20)　cm(2),　Omega(4)　=　7.41　X　10(-20)　cm(2)　and　Omega(6)　=　1.99　X　10(-20)　cm(2).　The　spectral　parameters　of　Ho3+　ions　were　also　calculated.　The　emission　spectrum　of　Gd0.9La0.1VO4　crystal　co-doped　with　Yb3+　and　Ho3+　ions　was　detected　when　the　sample　was　excited　by　LD　at　980　nm　and　the　intense　up-conversion　emissions　were　observed　at　550,　660　and　750　nm.　(c)　2005　Elsevier　B.V.　All　rights　reserved.