The invention belongs to the field of equipment detection, and particularly relates to an image-identification technology-based non-contact displacement detecting device and a method for detecting displacement of a detected device through the device. The device comprises an image acquisition module (1), a laser generation unit (2), a data storage and transmission module (3), a power supply and control module (5) and an objective target (8); the image acquisition module (1), the laser generation unit (2) and the data storage and transmission module (3) are connected with the power supply and the control module (5) separately; the image acquisition module (1) is connected with the data storage and transmission module (3); the distance between the image acquisition module (1) and the laser generation unit (2) is fixed; the objective target (8) is arranged on the detecting device; at least one of the exposed surfaces of the objective target (8) is provided with at least two patterns with geometric centers. The device has the advantages that convenience is brought to carrying and installation; the application range is wide, the adaptability is high, and the service life is long; the measurement method is simple, and the result is accurate; deformation and displacement in three directions can be detected at the same time, and the efficiency is high.