The invention relates to the filed of optical fiber communication and fiber laser, and particularly to a swept laser based on optical fluid. The swept laser based on the optical fluid comprises the components of a pump light source, a fiber wavelength division multiplexing device, an Er-doped fiber and a spectrum analyzer. The pump light source is connected with the fiber wavelength division multiplexing device. The output end of the fiber wavelength division multiplexing device is connected with the spectrum analyzer. The common end of the fiber wavelength division multiplexing device is welded with the Er-doped fiber. The end of the Er-doped fiber is cut to be flat and is fixed on a horizontal fiber clamp. The horizontal fiber clamp is fixed on a high-precision linear translation stage. The optical fluid is plated on the tail fiber of the flat cut Er-doped fiber.