The invention discloses a rapid modulation fluorescence polarization microscopic imaging device and method based on liquid crystal, and relates to the technical field of optical imaging. The device comprises a light source, an excitation filter, a liquid crystal polarization rotator, a dichroscope, an objective lens, an emission filter, a wave plate, an analyzer, an imaging lens, a camera, a liquid crystal controller and a computer. The method comprises the following steps: converting an emergent light beam of the light source into linearly polarized light through a liquid crystal polarizationrotator; after the linear polarization exciting light enters a sample, exciting the fluorescent light; enabling the fluorescent light to pass through the objective lens, the emission filter, the waveplate and the analyzer and then enter the camera target surface for imaging; in the process, enabling the computer to control the liquid crystal controller to drive the liquid crystal polarization rotator to modulate the polarization angle of the incident exciting light, controlling the camera to acquire a series of fluorescence polarization images, and then performing calculating according to the series of fluorescence polarization images to obtain each fluorescence parameter image. The device has the advantages of high imaging speed, high resolution, wide field of view, high modulation precision and the like, and has a good application prospect.