The invention discloses a method for searching a video, a system therefor and a device therefor as well as a video storing method and a system thereof. The method for searching the video comprises the following steps: performing motion detecting and tracking on a video sequence; if detecting a risk event existing in a video image, recording descriptive information of the risk event, wherein the descriptive information comprises at least an image identifier with the risk event; when searching the video image with the risk event, receiving a searching condition; matching the searching conditionand the recorded descriptive information of the risk event, if matched, obtaining the video image from a video storing device according to the image identifier in the descriptive information of the risk event, and displaying the video image to a user. The invention improves the video searching efficiency. Furthermore, the invention only stores the video image with the risk event, thereby saving the storing space.