A novel method for preconcentration of ultra-trace germanium and determination by hydride generation atomic fluorescence spectrometry (HGAFS) was presented in this work. When the pH values of solution were 6.0～8.0, the adsorption efficiency of nano-sized TiO2 colloid for germanium was 97.0%～99.0% in a short time. Nano-sized TiO2 colloid was used to concentrate the ultra-trace germanium in water sample due to its high absorption capacity. After centrifugation, the supernatant fluid was removed. The sediment which contained the concentrated Ge(Ⅳ) was inverted to colloid by adding HCl of certain concentration. Ge(Ⅳ) in colloid was directly determined by HGAFS. The proposed method possesses low detection limit (3σ) (0.060 μg·L-1) and good precision (the relative standard deviation (RSD) is 2.0%, n=6). The method is was also quite simple and time saving (without any filtration and desorption process). Satisfactory results were obtained when applying this method to the determination of ultra-trace germanium in water samples.