The evidences to be collected by the patentee are as follows 1. Evidence concerning the infringer. As the saying goes, know yourself and your enemy, and win every battle. Therefore, the exact name, address, nature of the enterprise, registered capital, number of personnel, business scope and other information of the infringer should be known first by the patentee. It is very important for patentees to know what strategies they should adopt to deal with patent infringement. 2. Evidence on the facts of infringement. The premise of patent infringement is that there must be infringement. Therefore, it is very important to prove that the infringer did infringe the patent right. The evidences in these aspects include the real object, photo, product catalog, sales invoice, purchase and sale contract, etc. 3. Evidence of damages. The patentee may claim damages from the infringer. The amount of damages claimed may be the loss suffered by the patentee. However, the patentee shall provide evidence to prove that due to the infringement of the other party, the sales volume of his own patented products is reduced, or the sales price is reduced, as well as other costs paid more or less. The main methods are as follows 1. Self evidence collection and attorney investigation and evidence collection 2. Apply for notarial organ to preserve evidence 3. Apply to the court for preservation of evidence before litigation 4. Apply to the people's court for obtaining evidence 5. Apply for investigation and evidence collection by administrative organsHow Patent website:http://www.guocai-lawfirm.com/patent/