The invention discloses a plant phenotypic information acquisition system and a plant phenotypic information extraction method, and belongs to the field of plant phenotypic information acquisition equipment. The information acquisition device of the invention comprises a visible-light camera and an adjusting mechanism for adjusting the position of the visible-light camera, is driven by a rotating device to rotate around a carrying table in order to acquire the phenotypic information of plants in different growth stages, can extract the phenotypic information of the plants from various angles, and achieves a good acquisition effect. The plant phenotypic information extraction method uses the acquisition device to acquire the plant phenotypic information, extracts images in the whole space of the plant at multiple angles by controlling the capture time of the visible-light camera, calculates the average value of the images, minimizes the influences of illumination inconsistency on different images, and reduces the measurement errors of phenotypic parameters such as leaf area, plant height and base diameter caused by the shielding of branches and leaves or spatial stretching and crimping of the leaves.