At first, we made a approximative λ/4-shifted DFB Yb-doped fiber laser with double exposure method.The length of Yb-doped fiber is 10cm. Secondly, we processed the fiber laser by UV trimming. In addition, the running characteristics of the λ/4 phase-shift DFB Yb3+-doped fiber CW lasers were researched. The fiber laser have thefollowing excellent characteristics: Output power of 25 mW, fluctuation of less than 2%, 100% single longitudinal mode,27 dB polarization extinction ratio, 60 dB signal-to-noise. What is more, the effect on the fiber lasers is also researched from several factors such as temperature, mechanism perturbation and fresnel reflection of fiber end section.