A cladding pumped Er/Yb co-doped double clad fiber ring laser operating in L-band is demonstrated. A 9-m-long Er 3+ /Yb 3+ co-doped fiber (EYDF) is used as the gain medium, and six diode lasers are used to cladding pump EYDF, by utilizing amplified spontaneous emission as a secondary pump source, the laser can operate in L-bandstably.Whenthepumpingpoweris3594.5mW,thepumppowerofenteringfiberismeasuredtobe2731.8mW and the maximum output power obtained is 518.4 mW, the slope efficiency is 19%. The laser output wavelength is 1613.94 nm, the 3 dB band width is 0.15 nm, and the side mode suppression ratio is about 50 dB.