The Ge-SiO2 and Ge/Al-SiO2 compound films were prepared by Radio-Frequency (RF) magnetron sputtering technique, and then Ge nanocrystals were obtained in the films by a thermal annealing treatment. The optical bandgaps of the Ge nanocrystals in the two films were calculated by measured UV-visible absorption spectral data, and the nonlinear optical properties of the two compound films were investigated by using picosecond laser Z-scan technique. Experiments show that the nonlinear absorption coefficients of Ge-SiO2 and Ge/Al-SiO2 films at 1 064 nm lasing are -1.23×10-7 m/V and 4.35×10-8 m/W, respectively. The former corresponds to the saturable absorption, while the latter corresponds to the two-photon absorption. Furthermore, both the Ge-SiO2 and Ge/Al-SiO2 films can be as the saturable absorbers to implement the passive Q-switching and mode-locking operation for a 1.06 μm laser. Obtained experimental results demonstrate that Ge/Al-SiO2 film could achieve narrower Q-switched pulse and mode-locked pulse than that of the Ge-SiO2 film. Finally, it discusses the mechanisms of passive Q-switching and passive mode-locking with the two films.