http://shanghai.usembassy-china. ... sked-questions.html
How long before my program starts can I travel to the US?
According to the U.S. Department of Homeland Security, student visa holders may enter the U.S. no earlier than 30 days before the start date listed on their I-20. This 30-day limit does not apply to returning students with a valid I-20; they may travel to the U.S. at any time.
以上是美国驻上海总领事馆签证处的官网上对于常见问题的回答。链接见第一行。
大使馆的网站上没有查到相关内容，如果实在不放心，可以到大使馆签证处的微博上去直接问他们。
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本帖最后由 一样的天空 于 2012-6-4 11:50 编辑 ].
