A simultaneously passively Q-switched and mode-locked (QML) Nd:GGG laser using a Bi-doped GaAs wafer as saturable absorber is accomplished for the first time. The Bi-doped GaAs wafer is fabricated by ion implantation and subsequent annealing. In comparison to the passively QML laser with GaAs, the QML laser with Bi-doped GaAs can generate more stable pulses with 99% modulation depth. The experiment results indicate that the Bi-doped GaAs could be an excellent saturable absorber for diode-pumped QML lasers.