Fluorapatite/hydroxyapatite solid solution has better biological properties than other apatites, especially used asfilms or coatings. In this work, sol-gel preparation and in vitro behavior of fluorapatite/hydroxyapatite solid solutionfilms on titanium alloy were investigated. Ca(NO3)2.4H2O and PO(OH)x(OEt)3-x were selected as precursors, andhexafluorophosphoric acid (HPF6) was used as a fluorine containing reagent. The Ca and P precursors were mixedwith HPF6 to keep the Ca/P molar ratio 1.67. The mixtures refluxed for 12 h were used as dipping sols for thepreparation of the films. The phase of the films obtained at 600℃ was apatite. The F contents in the films increasedwith the concentrations of HPF6 in the dipping sols. The solid solution films were shown to have better stabilitythan hydroxyapatite films, and a reasonably good bioactivity in the in vitro evaluation.