Abstract: Surveillance video is used for watching known threats in real time .Video Surveillance is used to observe unusual activity going on to prevent crime. Today most shop owners have CCTV cameras to record, these uncertain activities but these systems do not detect theft. If a system to detect theft which is efficient and faster is not designed, then it would be difficult to detect theft. The existing systems currently present in the market are CCTV, Sensor and Trip Wires. This paper represents the detecting a crime taking place in an enclosed environment and catch the theft in an efficient manner .This paper uses Canny edge detection algorithm to prevent theft. As this technique provides total security by detecting and catching of unusual activity happening. Moreover, proposed system does not waste its memory by recording the activity unnecessarily. Hence saves lot of wastage of memory of hard disk.Keywords: Intrusion detection, Security, Video surveillance, Edge detection, Grabbing