概述
不论是首次申请美国签证或者续签，申请流程大致相同。需要注意的是：即使您护照到期，但签证可能仍然有效。您可以使用包含有效签证的旧护照和有效的新护照去美国旅行。
您可使用签证代传递服务加快申请流程。大多数情况下，使用该服务则无需前往使/领事馆进行面谈。但是，同面谈一样，代传递服务并不能保证签证申请成功。而且在某些情况下，使/领事馆在审查通过代传递服务提交的申请之后，可能要求申请人亲自来面谈。
条件

• 14岁以下和80岁（含）以上的申请人，如果没有美国签证拒签史，则可通过代传递服务申请签证。申请人必须为中国公民或居民且本人在中国。
• 您以前的美国签证在到期后48个月之内进行续签。

所有申请人需要材料：
1、My DS160 application form confirmation page has been included in the application. DS160申请表确认页
2、My photo was taken less than six months ago and has not been previously used.
My photo is in color with a white background, and I am facing forward.
My photo is 2 in. by 2 in. (51mmX51mm).
My photo shows my full face, neck, and ears. If I am wearing glasses, there is no glare.
My photo has not been digitally altered and I am not wearing colored contacts. 
一张照片： 2寸正方形(51mm x 51mm)彩色正面证件照，正面照，最近六个月内拍摄，白色背景。
3、 My passport will be valid for at least six months beyond my intended period of stay.
护照： 护照有效期需超出在美预定停留期至少六个月；
4 、I have already provided all fingerprints with a previous visa application
采集过指纹
5 、Drop Box Confirmation Letter文件提交信并签字

F1 Applicants：F1学生签证续签所需材料：

• I have verified that my current SEVIS status is Initial or Active, and Paid

申请人确认自己已经交过SEVIS fee 200美金

• I have submitted an original I-20, signed by the school within the last year (F-visa).

提交I-20原件,由学校指定官员签字

• I have submitted unsealed, official transcripts from the U.S. school that I most recently attended (F-visa ) 提交美国教育机构所授课程的官方成绩单，请确保装有这些资料和文件的信封必须是打开的
• Research/study plans with detailed information about your planned studies or research in the United States, including the name and e-mail address of your advising professor and/or the head of your department in the United States.

赴美研究/学习计划及相关的详细信息，其中包括美国学校的导师和/或系主任的姓名及电子邮箱地址。

• A resume/CV that provides detailed information about your past academic and professional experience, including a complete list of all publications to which you have contributed.

一份详细说明以往学术和专业经验的简历，其中包括投过稿的出版物完整清单。

• An advisor’s biography, CV, or webpage printout (for graduate students who have already been assigned an advising professor at their U.S. institution).

导师的个人简介、简历或打印网页（针对所在美国教育机构已为其指定导师的研究生）

B2 签证续签所需材料：
Travelers: Include a copy of the invitation letter, itinerary。
旅客： 需提供的文件包括：一份邀请函或行程表