Abstract: In order to resolve the low output energy of active mode-locked laser and instability of passive mode-locked laser, Cr4+:YAG passive mode-locker and acousto-optic active mode-locker were used jointly for Nd:YAG laser mode-locking. The output characteristics of passively mode-locked by Cr4+:YAG only, actively mode-locked by acousto-optic mode-locker only and mode-locked by Cr4+:YAG and acousto-optic jointly were analyzed and compared through experiments. Results showed that the joint mode-locking method gave good resolution to the low output energy and stability, and the mode-lock amplitude and energy fluctuation were less than 5％, with the depth of mode locking of 100%, pulse width less than 450ps and output energy near 200mJ at 1064nm wavelength. Adding KTP crystal out of the cavity, the output conversion efficiency was about 41% at 532nm wavelength．The results show the possibility of actively-passively mode-locked technology and it is helpful for the development of mode-locking technology.