A multiwavelength fiber laser with symmetrical nonlinear optical loop mirror, from which up to 8 wavelengths can be generated, has been proposed and demonstrated. The intensity-dependent transmission of nonlinear optical loop mirror due to nonlinear polarization rotation effect is used to alleviate the mode competition in the homogeneous broadening gain medium of erbium-doped fiber. Besides, a novel comb-like filter i.e. birefringence fiber filter is proposed and utilized, which has in-line configuration. At the same time, the effect of the 980 nm pump power on the multiwavelength generation has be investigated. It is shown that the pump power contribute a lot to the evenness of the multiwavelength spectra.