Patent legal status refers to the legal status of a patent application when it is entered into the patent document database. Patents are not obtained once applied for, but also need to go through a series of review procedures. During the review process, the applicant may take the initiative. The patent application is abandoned, perhaps rejected by the patent office, and the legal status changes. Legal status can be roughly divided into three types: The first is an unstable status, such as the "publication" and "substantive examination" of invention patent applications, that is, the situation is waiting for review or review is in progress; the second is relatively stable. status, that is, the "authorized" status after review. Some patents may be maintained until "expiration", and some may be "terminated" due to failure to pay annual fees on time; the third is a stable state, such as "withdrawal" after publication, review "Deemed withdrawn", "rejected" during the process, "abandoned", "deemed abandoned" after authorization, and "revoked" or "invalid"; at this point, the case is closed and there will be no further changes.