A new kind of single-longitudinal-mode, wavelength-switchable fiber laser is proposed and experimentally demonstrated in this paper. Such fiber laser has the Fabry-Perot (F-P) cavity and uses 980 nm pumped erbium-doped fiber (EDF) as gain media. And an umpumped EDF in the cavity is used as the saturable absorber to achieve single-longitudinal-mode operation, meanwhile a 1×N optical fiber switch and N parallel fiber Bragg gratings (FBGs) are used as the wavelength selection module to achieve wavelength-switchable operation. With 90 mW pumping power, the single-longitudinal-mode laser with -0.5 dBm peak power and 3.6 kHz linewidth is generated; And the wavelength can be randomly switched among the wavelengths of 1574.6 nm, 1579.7 nm, 1584.8 nm and 1589.9 nm by applying the suitable electrical signal to fiber switch.