The key technologies of achieving room-temperature stable multi-wavelength fiber lasers (MWFLs) are how to restrain the homogeneous broadening effect of the doped fiber at room temperature. We summarize the main technologies and methods reported recently to realize the room-temperature MWFLs, and introduce our innovative works in this field, including proposing several novel structures and operable technologies of switchable multi-wavelength fiber lasers using special fiber Bragg gratings (FBG) with several resonance peaks, such as FBG in multimode fiber, FBG in polarization maintaining fiber and sampled FBG. Switchable multi-wavelength fiber lasing oscillations with less than 2 nm wavelength spacing, tunable wavelength and spacing and excellent room-temperature stability were demonstrated and realized. Two other erbium-doped MWFL designs are proposed respectively by using nonlinear polarization rotation (NPR) effect and a nonlinear optical loop mirror (NOLM) to induce intensity-dependent loss. As a result, power-stable, broad bandwidth and uniform multiwavelength operations are obtained for both laser sources. Up to 50 wavelengths lasing oscillations with wavelength spacing of 0.8 nm within a 3 dB spectral range of 1562～1605 nm have been achieved. The measured power fluctuation of each wavelength is about 0.1 dB within a two-hour period.