The right of first use of a trademark is the right of the first user of a trademark to defend against the right of prohibition by the owner of the exclusive right to use a registered trademark. From a positive point of view, after the trademark registrant obtains the trademark registration, the first user of the trademark can still Continue to use the trademark. However, the first user should use it earlier than the trademark registrant, and it should be subjectively good-faith. The first user must be continuous use and the logo has gained a certain influence, and the continued use must also be within the original scope. "Certain impact" is different from being well-known. It means that the first-used mark is widely known by the relevant public in a specific area. Different from the "certain impact" in the first-use defense clause, the "certain influence" in the trademark registration prevention clause requires that the trademark be used first. It should have a stronger impact over a larger geographical area. The determination of "original scope" should be based on a comprehensive consideration of regional factors, trademark identity, and categories of goods or services.