According to the provisions of Chinese trademark law, if a trademark has not been used continuously for three years, anyone else could file a request to cancel this trademark. Then the trademark office would send a notification to ask the trademark holder to respond and amend in limited time frame. In that case, the defendant needs to provide evidence to respond and prove it.
 
How to provide the evidence or what the evidence should be?
 
In brief, the evidence could be the agreement or brochures or advertisement or invoice or anything else which can prove that you had ever used the trademark within the past 3 years from the date which the request was filed. But if you have registered the trademark in separated classes, you must provide the use evidence in all of the classes, if not, it can only prove that you have used the trademark in parts of the classes of the trademark when the evidences have been accepted, and the trademark in other classes would be cancelled. Meanwhile, the defendant has to collect and respond to the Trademark office within 2 months or file the legitimate reason of non-use of the trademark, the legitimate reason which are acceptable are as follow:
 
1) Force majeure;
 
2) Stop of using because of the national policy;
 
3) Stop of using because of the bankruptcy liquidation; 
 
4) Other reasons which can be accepted by the trademark office.
  
When you file the evidence, the following suggestions need to be aware:
 
1) The original use evidence is much better than their copies, for example, kinds of the agreements with your business partner related the trademark which was mentioned in the cancellation request and it would be better has the seal on the perforation.
 
2) The brochures or advertisements with your trademark on it which can be proved that those were used within said 3 years and include the designated classes of the registered trademark, and all of the brochures or advertisements must be proved were used within said 3 years. The cost incurred by the advertisements and the brochures, the invoice send by the printer, the publication name, publishing house, publishing time and so on result the chain of the evidence.
 
3) About the commercial voucher, it must be the original and not the one used inside of your company or partners.
 
4) Some official documents from the official office are much believable than others.