F-1留学生OPT申请要点：最多12个月须与专业直接相关，STEM可再延24个月
美国公民及移民服务局现行说明显示，持 F-1 签证的留学生可以申请选择性实习培训（OPT），这是与本人主修专业直接相关的临时就业许可。临近毕业季，这条通道的几个硬条件值得提前对清楚。
时长是这样算的：符合条件的学生可以在完成学业前（pre-completion）和完成学业后（post-completion）合计申请最多12个月的 OPT，毕业前用掉的时间要从毕业后的可用时长里扣掉。所有 OPT 工作都必须与主修专业直接相关。
申请顺序不能颠倒。第一步是请学校的指定校方负责人（DSO）在学生的 I-20 表格上背书推荐，并在学生和访问者信息系统（SEVIS）里做好记录；第二步是向移民局递交 I-765 就业许可申请表，连同费用和表格说明要求的材料一起交。拿到移民局签发的就业许可文件（EAD）之后才能开始工作。
理工科学生多一条路：持有列在 STEM 指定学位项目清单上的学士、硕士或博士学位的学生，可以在 DSO 推荐和移民局批准后，再申请24个月的 STEM OPT 延期。
还有两个容易踩的点。一是转学或升读新学位（比如本科毕业接着读硕士）会让原有 OPT 就业许可自动终止，在已终止的 EAD 上继续工作属于无许可工作，后果包括被要求离境和再入境受限。二是人在 OPT 期间仍然是 F-1 身份，保持身份的要求一项都不能少。
（来源：美国公民及移民服务局）
OPT for F-1 Students: Up to 12 Months Tied to the Major, Plus a 24-Month STEM Extension
Current guidance from U.S. Citizenship and Immigration Services explains that F-1 students may apply for Optional Practical Training (OPT), temporary employment directly related to the student's major area of study. As graduation season approaches, several hard conditions in this channel are worth checking early.
The time is counted this way: eligible students can receive up to 12 months of OPT employment authorization before completing their studies (pre-completion) and/or after completing them (post-completion), and all periods of pre-completion OPT are deducted from the available post-completion period. All OPT employment must be directly related to the major.
The order of steps cannot be reversed. First, the designated school official (DSO) must recommend the OPT by endorsing the student's Form I-20 and making the appropriate notation in the Student and Exchange Visitor Information System (SEVIS). Second, the student properly files Form I-765, Application for Employment Authorization, with USCIS, with the required fee and supporting documentation. Work may begin only after USCIS approves the application and issues the employment authorization document (EAD).
Students in science, technology, engineering and mathematics have one more path: holders of a bachelor's, master's or doctorate degree on the STEM Designated Degree Program List may apply for a 24-month STEM OPT extension, again with DSO endorsement and USCIS approval.
Two pitfalls deserve attention. Transferring to a different school or beginning study at another educational level automatically terminates OPT authorization, and working on a terminated EAD is unauthorized employment with serious consequences, including removal and reentry bars. And a student on OPT remains in F-1 status, so every requirement for maintaining student status still applies.
(Source: U.S. Citizenship and Immigration Services)
来源：美国公民及移民服务局
发布：GSM·美国（发布链接）
图片来源：图：大学图书馆里正在学习的学生们。照片：Gary Todd，CC0，经维基共享资源。 / Photo: Students studying inside a university library. Photo: Gary Todd, CC0, via Wikimedia Commons
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