A Q-switched ytterbium-doped fiber laser(YDFL)is proposed and demonstrated using a newly developed multi-walled carbon nanotubes polyethylene oxide(MWCNTs-PEO)film as a passive saturable absorber(SA).The saturable absorber is prepared by mixing the MWCNTs homogeneous solution into a dilute PEO polymer solution before it is left to dry at room temperature to produce thin film.Then the film is sandwiched between two FC/PC fiber connectors and integrated into the laser cavity for Q-switching pulse generation.The laser generates a stable pulse operating at wavelength of 1060.2 nm with a threshold pump power of 53.43 mW.The YDFL generates a stable pulse train with repetition rates ranging from7.92 to 24.27 kHz by varying 980-nm pump power from 53.42 to 65.72 mW.At 59.55-mW pump power,the lowest pulse width and the highest pulse energy are obtained at 12.18μs and 143.5 nJ,respectively. A Q-switched ytterbium-doped fiber laser (YDFL) is proposed and demonstrated using a newly developed multi-walled carbon nanotubes polyethylene oxide (MWCNTs-PEO) film as a passive saturable absorber (SA). The saturable absorber is prepared by mixing the MWCNTs homogeneous solution into a dilute PEO polymer solution before it is left to dry at room temperature to produce thin film.Then the film is sandwiched between two FC / PC fiber connectors and integrated into the laser cavity for Q-switching pulse generation. Laser generates a stable pulse operating at wavelength of 1060.2 nm with a threshold pump power of 53.43 mW. The YDFL generates a stable pulse train with repetition intervals ranging from 7.92 to 24.27 kHz by varying 980-nm pump power from 53.42 to 65.72 mW.At 59.55-mW pump power, the lowest pulse width and the highest pulse energy are obtained at 12.18 μs and 143.5 nJ, respectively.