An all-fiber linearly polarized Raman fiber laser at 1 120 nm is demonstrated. With a 1 070-nm linearly polarized Yb-doped fiber laser as pump source, an output of up to 7.7 W at 1 120 nm is obtained with an optical efficiency of 55%. The polarization extinction ratio of the linearly polarized Raman fiber is higher than 18 dB. A numerical simulation model is developed to determine the Raman coefficient of the gain fiber and to evaluate the laser performance. The spectral isolation between the Raman fiber laser and the pump fiber laser is determined to be necessary for further improvements of performance.