The Polytitanocarbosilane with the molar ratio of Ti:Si=1:10 had been prepared by the reaction of polycarbosilane with polytitanosiloxane. This polymer had excellent spinnability and stability. After being melt spinning and unmelting treatment，followed by heat treatment at 1300℃ in the presence of nitrogen atmosphere，the SiC fiber with high molar ratio of Ti/Si was obtained. The synthesis and structure of cited polytitanosiloxane，its reaction process with polycarbosilane，and the pyrolytic properties of polytitanocarbosilane were examined and discussed.