A high-power and high-efficiency GaAs/AlGaAs-based terahertz (THz) quantum cascade laser structure emitting at 3.3 THz is presented.The structure is based on a hybrid bound-to-continuum transition and resonant-phonon extraction active region combined with a semi-insulating surface-plasmon waveguide.By optimizing material structure and device processing,the peak optical output power of 758mW with a threshold current density of 120 A /cm2 and a wall-plug efficiency of 0.92％ at 10K and 404mW at 77K are obtained in pulsed operation.The maximum operating temperature is as high as 115K.In the cw mode,a record optical output power of 160mW with a threshold current density of 178 A/cm2 and a wall-plug efficiency of 1.32％ is achieved at 10 K.