Legal analysis: Well-known trademarks do not have the problem of the length of validity. There is no accurate concept of the term of protection of well-known trademarks, because the validity period of trademarks after registration is 1 years, even if they are well-known trademarks, they need to be renewed after 1 years. If it is not renewed after expiration, the well-known trademark will also be cancelled. Others can also apply for this trademark again.

Legal basis: Trademark Law of the People's Republic of China

Article 39 A registered trademark is valid for ten years, counting from the date of approval of registration.

Article 4 Where a registered trademark needs to be used continuously after its expiration, the trademark registrant shall go through the renewal procedures in accordance with the regulations within 12 months before the expiration; If it fails to be handled during this period, a six-month extension period may be granted. The validity period of each renewal registration is ten years, counting from the day after the last expiration of the trademark. If the renewal formalities are not completed at the expiration of the period, the registered trademark shall be cancelled.

the trademark office shall announce the renewed registered trademark.