In this paper, the Yb3+-dopedring cavity fiber laser is compared with the F-P cavity fiber laser which were both pumpedby LD with fiber pigtail. It is found that the lasing wavelength will be changed when thestructure of cavity is varied. And it is also found that the Yb3+-doped ringcavity fiber laser have lower cavity loss and pump threshold, while F-P cavity fiber laserhas narrower FWHM.