An all-fiber based Er3+∶Yb3+ co-doped double clad fiber laser operating at 1 550 nm is demonstrated. By using 9 m long Er3+∶Yb3+ co-doped fiber(EYDF) as the gain medium, and using a pair of fiber Bragg gratings as wavelength filters, the line-width of the output laser is as narrow as 0.2 nm and the output power is more than 6 mW. The fluorescent effect of the laser before its emission is also studied. And it is found that the Er3+∶Yb3+ co-doped double-clad fiber laser also exhibits a high gain for Yb3+ transition near 1 080 nm.