The invention relates to a high-definition infrared fingerprint acquisition device, and aims at solving the problems that the existing acquisition device is apt to be interfered by conditions and the definition cannot satisfy requirements. The high-definition infrared fingerprint acquisition device consists of a non-isosceles trapezoidal prism, a light source, lenses, a photoelectric detector and a plastic molded pipe support which is used for shielding ambient light and supporting the parts and has a rectangular cross section. The trapezoidal prism with an inclined acquisition surface is obliquely assembled on the plastic molded pipe support. A fingerprint acquisition light path sequentially consists of the trapezoidal prism, a Huygens lens set and the photoelectric detector. A fingerprint acquisition surface is arranged on the lower base surface of the trapezoidal prism, an oblique leg surface adjacent to the larger base angle of the trapezoidal prism is an optical transmission surface and the light source is configured on the upper base surface of the trapezoidal prism. The light source is an infrared light source. An oblique leg surface adjacent to the smaller base angle of the trapezoidal lens is used as an optical black substrate which is coated with black paint. An infrared light filter is additionally assembled between the lenses and the photoelectric detector or between the lenses. The upper base surface of the trapezoidal prism is a rough surface. The high-definition infrared fingerprint acquisition device has the advantages of high acquired image definition, evenness, small deformation rate, low distortion rate, high imaging quality, strong image contrast, bright lines, resistance to external ambient light interference, high dry and wet fingerprint acquisition sensitivity, simple structure and convenience in manufacturing, installation and use.