Legal analysis: the use of a trademark before it is declared invalid may also constitute infringement, because after the trademark is declared invalid by the trademark office according to law, it means that it has no legal effect from beginning to end. In this case, using the same or similar trademark as the other party should be regarded as trademark infringement, but similar cases should be applied to the Trademark Office first.

Legal basis: Article 47 of the Trademark Law of People's Republic of China (PRC) A registered trademark that has been declared invalid according to the provisions of Articles 44 and 45 of this Law shall be announced by the Trademark Office, and the exclusive right to use the registered trademark shall be deemed as nonexistent from the beginning. The decision or ruling declaring a registered trademark invalid has no retrospective effect on the judgment or ruling of trademark infringement cases made and executed by the people's court before the invalidation, the conciliation statement, the decision on handling trademark infringement cases made and executed by the administrative department for industry and commerce, and the trademark transfer or use license contract that has been performed. However, if losses are caused to others due to the malice of the trademark registrant, compensation shall be made. If the trademark infringement compensation, trademark transfer fee and trademark use fee are not returned in accordance with the provisions of the preceding paragraph, which obviously violates the principle of fairness, they shall be returned in whole or in part.

Article 111 of the Civil Procedure Law of People's Republic of China (PRC), if a litigant participant or other person commits one of the following acts, the people's court may impose a fine or detention according to the seriousness of the case; If the case constitutes a crime, criminal responsibility shall be investigated according to law: (1) forging or destroying important evidence, which hinders the people's court from hearing the case; (2) using violence, threats or bribes to prevent witnesses from testifying or instigating, bribing or coercing others to commit perjury; (3) Hiding, transferring, selling off or destroying the property that has been sealed up or detained, or transferring the property that has been counted and ordered to be kept; (4) Insulting, slandering, framing, beating or retaliating against judicial personnel, participants in litigation, witnesses, translators, expert witnesses, inspectors and assisting executors; (5) Obstructing judicial personnel from performing their duties by violence, threat or other means; (6) Refusing to perform a legally effective judgment or ruling of the people's court. The people's court may impose a fine or detention on a unit that commits one of the acts listed in the preceding paragraph; If a crime is constituted, criminal responsibility shall be investigated according to law.