To attend a U.S. non-immigrant visa interview in Chengdu, you must bring several mandatory documents, starting with a passport valid for at least six months beyond your intended stay and any previous passports containing prior U.S. visas. You are required to present the printed confirmation page of your DS-160 online application, which features a ten-digit barcode, along with your interview appointment confirmation letter. Additionally, bring one color photograph (2x2 inches or 51x51mm) taken within the last six months that meets specific U.S. visa requirements, and the original receipt for your visa application fee payment. Depending on your purpose of travel, it is highly recommended to bring supporting documents such as an employment letter detailing your position and salary, bank statements or pay slips from the past three months to prove financial solvency, and a detailed travel itinerary. Students should provide their most recent school transcripts and diplomas, while those visiting relatives should bring copies of their host's legal status in the United States. Ensure all documents are organized and accessible, and remember that applicants under 18 years of age must also bring their household registration (hukou) and be accompanied by at least one parent.