原来的美国十年签证还有效吗？
10年签证，英文叫Multi-Entry Visa 或者 Multiple Entry Visa， 是多次入境签证的意思. 在中国申请的最长的是B1/B2(即旅游、商业签)和C1/D(即Transit Visa， 过境签)， 为10年有效期的多次入境签证，每次入境可以停留6个月。 中国居民也可以申请一年/二年有效的10年期 B1/B2 和 C1/D (根据你申请的入境口岸而不同)的多次入境签证， 但只能在中国出境后（例如从香港到美国）第一次使用。
如果以前有美国有效签证但过期了怎么办？ 有两种情况： 一是在美国过期的；二是从其他国家去美国时在美国海关被要求作废以前签证时的旧签证。 第一种情况比较麻烦一些，因为在办理新签证时会要求出示旧护照上的所有签证页，包括美国的移民或非移民签证页。所以如果你的旧护照上有其它国家有效的签证的话就会比较麻烦了... 第二种其实更简单些，因为只涉及一本护照而已。不过要注意，虽然海关人员可以要求你作废某次入境的美国签证，但他没有权利决定要不要给你下一次入境的机会。因此如果你上次入境是商务或是旅游签证（B1\B2），这次又是以同样的理由来美国的话，还是有可能会被拒绝入境的哦！ 所以还是重新申请一个10年的好。
另外就是美国签证分为很多种类的，不同的种类有不同的有效期以及可以入境的次数和停留时间限制，具体参见URL 从上面链接中的Visas for Chinese Citizens一栏可以看到目前只有两类中国的居民可以申请10年期多次入境签证： A1，A2 and G5 visas are issued to diplomatic officials， their immediate families or staff， as well as other U.S. government employees. These visas do not allow holders to work in the United States but there is no restriction on multiple entries into the USA. C1， D1， DS1 and DS2 visas are all valid only once， allowing the holder to transit through US international airports on flights to another country without entry. Please note that if you apply from China， your visa will be printed with a date of "valid until" which should correspond to the latest day possible to leave after entering via this route. As a result these visas cannot legitimately be used by tourists who intend to spend more than six months outside the U.S. If the immigration authorities discover they have been misused， such visitors could face detention， fines and deportation. B1 and B2 visas can be obtained for tourist， business or visiting relatives visits. They last ten years and grant up to six month stays per visit to the United States. In some cases， visa holders may be granted permission to remain longer or reenter at a later date upon application to an American consular official. However， please remember that it is illegal to use them beyond what was stipulated on your original visa stamp even if authorized by a consular officer． The most common B1 and B2 visas expire seven years from the date stamped on the passport rather than the actual issue date of the visa. This means that while one year has passed since issuance， any given visa