The present disclosure relates to security system and method based on sound field variation pattern. The present disclosure identifies a slow variation pattern of a acoustic transfer function occurring due to a gradual change in temperature and humidity of air according to a change in time and a change in a characteristic of an acoustic element, from a sudden sound field variation pattern within an internal space occurring due to an intrusion from an outside, activation of an air conditioning and heating device, and the like, or within a surveillance space induced by a change in an acoustic physical property. The present disclosure identifies sound field variation patterns occurring due to a change in an acoustic structure by an intrusion and a change in temperature and convection by air conditioning and heating. The present disclosure stores and verifies image information using an image obtaining apparatus.