After the trademark is declared invalid, it cannot be used, otherwise it will bear legal responsibility. The circumstances of declaring a trademark invalid are: (1) the registered trademark has obvious defects 1, which violates the prohibitive provisions of the Trademark Law. That is, in violation of Article 10 of the Trademark Law, the use of registered trademarks is prohibited as a sign of trademark use; In violation of Article 1 1 of the Trademark Law, the use of a registered trademark is prohibited by law as a sign of the use of a registered trademark; In violation of Article 12 of the Trademark Law, a registered three-dimensional trademark is a sign without distinctive features and cannot be registered. 2. Obtaining registration by deception. This means that when applying for trademark registration, the owner of a registered trademark obtains registration by means of fiction, concealing facts or forging application documents and other relevant supporting documents, such as forging business licenses, forging approval documents of drug or tobacco management departments, forging certificates of origin, etc. (2) It is more complicated for a person who obtains the registered trademark right by improper means to obtain the registration by infringing upon others' prior rights, malicious cybersquatting, infringing upon others' business reputation and other improper means. 1. Infringe upon the prior rights of others. This trademark right is invalid because the applicant applies for the registration of the rights enjoyed by others as his own trademark, which is an infringement and cannot be tolerated by the law. 2. Malicious registration. Specific cases of malicious registration are: (1) preemptively registering trademarks that others have used and have certain influence; (two) the trademark applied for registration on the same or similar goods is a well-known trademark copied, imitated or translated by others, and it is not registered in China, which is likely to cause confusion; (3) The trademark applied for registration on different or similar goods is a copy, imitation or translation of a well-known trademark registered in China by others, which misleads the public and may harm the interests of the registrant of the well-known trademark; (4) Without authorization, the agent or representative registers the business target of the principal or representative in his own name; (5) The trademark contains a geographical indication of the commodity, and the commodity does not come from the area marked by the mark, and the trademark owner maliciously applied for registration and obtained approval. (III) Disputes over Registered Trademarks According to the principle of prior protection, the owner of a previously registered trademark has the right to request the cancellation of a registered trademark. It seems that some people are not clear about the legal consequences of invalid trademarks. Originally, after a trademark is invalid, it will bear civil liability to the real trademark owner because of its previous use behavior, and it is very likely that it has been investigated for administrative responsibility. However, if the trademark is used unscrupulously after it is invalid, the possibility of being sentenced is not without.