Distributed feedback quantum cascade lasers lased at 3.0 THz were prepared and their output performance was analyzed. The optimized grating parameters were obtained by theoretical analyses. Single-mode emission was obtained and a maximum output power of more than 166 mW at 15 K was achieved. The corresponding threshold current density was 257A/c m 2, and the side-mode suppression ratio was more than 15 dB. By changing the input voltage, the frequency was stable with a variation of less than 3 GHz. A beam with obviously fast and slow axis features was observed. Further improvement and the potential application of distributed feedback quantum cascade lasers are discussed.