The invention provides an optical fiber laser device and an optical system, and relates to the technical field of the laser. The optical fiber laser device comprises a pumping light source, a multifunctional optical fiber device, a cavity length adjusting module, and a polarization controller, wherein the pumping light source and the polarization controller are respectively coupled with the multifunctional optical fiber device; the multifunctional optical fiber device is coupled with the cavity length adjusting module; the cavity length adjusting module is coupled with the polarization controller; a gain optical fiber is arranged between the multifunctional optical fiber device and the cavity length adjusting module; an external signal input port is arranged at the cavity length adjusting module, and the cavity length adjusting module is used for changing the passing optical distance of the light in the cavity length adjusting module according to the input cavity length adjusting signal. Compared with the prior art, the oscillation repetition frequency of the optical fiber laser device provided by the embodiment of the invention is adjustable; the optical fiber laser device has good frequency stability, and can realize the ultra-short pulse output with high repetition frequency and high stability.