In order to obtain stable multi-wavelength lasing output lines with ultra-narr ow wavelength spacing,a multi-wavelength semiconductor optical amplifier (SOA) fiber laser based on nonlinear polarization rotation (NPR) effect and nonlinear optical loop mirror (NOLM) is designed and experimentally demonstrated.Due to th e NPR effect of SOA,the intensity-dependent loss (IDL) is induced by the combin ation consisting of SOA and polarization devices to suppress mode competition ef fect within homogenous broadening linewidth of SOA for achieving stable multiwav elength output.The Lyot-sagnac filter is designed to serves as a wavelength sel ection device,which composes of a section of 71m long polarization-maintaining fiber (PMF) for ultra-narrow wavelength spacing.In addition,the NOLM in the fi ber laser serves as the intensity equalizer to suppress mode competition effect furtherly and it also achieves power equalization and improve side mode suppress ion ratio (SMSR).By carefully adjusting the angels of polarization controllers ( PCs),stable multiwavelength lasing lines with power equalization has been achie ved at room temperature.The number of lasing lines is up to 184with wavelength spacing of 0.08nm within 10dB bandwidth.The SMSR is about up to 22dB.The desi gned fiber laser can be used as a light source in dense wavelength division mult iplexing (DWDM) optical communication system.