A four-wave mixing (FWM) assisted dual-wavelength erbium-doped fiber laser with a tilted fiber Bragg grating (TFBG) for wavelength switch is reported. The transverse-offset-spliced tilted fiber grating on single-mode fiber ensures that the two effective reflectivities of the reverse LP01 mode and LP11 mode are close enough to realize the dual-wavelength switch for laser. FWM process induced by high-nonlinearity photonic crystal fiber (HNL-PCF) avoids mode competition and ensures stable dual-wavelength oscillation at room temperature. The conjunction of a polarization controller (PC) and a polarizer introduces wavelength-dependent cavity loss and balances the reflectivity difference of the two wavelengths. By adjusting the intracavity polarization state, the proposed laser can operate in stable dual-wavelength or switch between two wavelengths at room temperature. The two lasing lines have a high signal-noise-ratio (OSNR) more than 45 dB and a maximum power fluctuation of 0.8 dB.