The invention discloses an image-processing-technology-based plane footprint detection and analysis system and a method thereof. The system comprises an image processing subsystem used for extracting the footprint depth information of a source plane footprint image, and generating a target plane footprint image which carries the depth information. In such a way, by means of a computer system, the depth information in a restored plane footprint image is further analyzed to show a stress pressure, an abrasive surface, foot rising and falling and the like, reflecting the gait feature and the figure feature of a person, of a footprint; and specific indexes, such as the sex, the stature, the posture, the age, the step gait and the like, of a suspect are obtained by combining the footprint left on-site for performing contrastive analysis, and detecting aided with the functions such as butting, splicing, overlapping, gridding, measuring, feature marking and the like; therefore, the aims of reducing a screening object range and determining the identity of the suspect are fulfilled.