(a), in violation of the relevant provisions of the Trademark Law, or by deception or other improper means to obtain registration, the Trademark Office may declare the registered trademark invalid, or other units or individuals may request the Trademark Review and Adjudication Board to declare the registered trademark invalid. In this case, we should be familiar with the relevant legal requirements from the beginning of trademark registration, and obtain trademark rights through legal and formal channels to avoid trademark invalidation. Then, what should I do if the registered trademark is accidentally injured? If it is declared invalid by the Trademark Office, the trademark owner shall make a request to the Trademark Review and Adjudication Board within 15 days after receiving the notice, and the Trademark Review and Adjudication Board will make a fair judgment. If the trademark is still declared invalid, it will make a decision. The last chance is to bring a lawsuit to the people's court within 30 days from the date of receiving the notice. If the trademark was originally declared invalid by the Trademark Review and Adjudication Board, then after receiving the Notice of Defense within the time limit of the Trademark Review and Adjudication Board, collect data and evidence to prove that the trademark was declared invalid within the specified time. Similarly, if the trademark is still declared invalid, you can bring a lawsuit to the people's court within 30 days. (2) Within five years from the date of trademark registration (there is no limit to the five-year period for malicious cybersquatting of well-known trademarks), the prior obligee or interested party may request the Trademark Review and Adjudication Board to declare the registered trademark invalid. First of all, at the beginning of trademark registration, don't take the shortcut of famous brands, shanzhai or grabbing famous brands, but firmly believe that you designed and registered your own trademark, and make yourself famous and add value through your own use. If this happens, first, you should reply within a time limit according to the notification requirements of the Trademark Review and Adjudication Board; Secondly, if a party refuses to accept the ruling of the Trademark Review and Adjudication Board, he may bring a lawsuit to the people's court within 30 days from the date of receiving the notice. It is best for professionals who are familiar with laws, regulations and relevant experience to deal with the crisis of trademark invalidation. To sum up, when a registered trademark is declared invalid, we should actively look for the reasons for invalidation, find out the main reasons for invalidation, distinguish different situations, and take corresponding measures according to relevant circumstances. Otherwise, once it is declared invalid, it will be a huge loss to the trademark owner. Of course, the best way is to avoid the situation that may be declared invalid from the root, so as not to be declared invalid when registering.