You can search by entering keywords on the patent search page in official website, China National Intellectual Property Administration, but only published patent documents can be searched, among which invention patents will not be published until 6-18 months after the new application is submitted, and utility model and design patents can only be published if authorized. You can also entrust a special patent agency to search the existing technology for the technical scheme.
Patent search is about searching for similar patents in terms of intellectual property rights, patent evaluation, reducing application risks and increasing authorization opportunities.