If you come to China with something urgent, and there isn’t enough time for you to apply for visa in a Chinese overseas office, you can apply for visa from a port visa office authorized by Ministry of Public Security, if you have an invitation letter from a Chinese authorized organization and have ordinary passport issued by the country which has diplomatic relations with China or has official trade contacts with China.
外国人因急事来华，而又来不及在中国驻外机关申办签证的，只要持有中国国内被授权单位的邀请函电，并持有与中国有外交关系或者官方贸易往来国家的普通护照，就可以向经国家公安部授权的口岸签证机关申请办理签证。
The port visa offices are set in Beijing, Shanghai, Tianjin, Dalian, Fuzhou, Xiamen, Xi’an, Guilin, Hangzhou, Kunming, Guangzhou (Baiyun Airport), Shenzhen (Luohu, Huanggang, Shekou), Zhuhai (Gongbei), etc.
口岸签证机关设在：北京、上海、天津、大连、福州、厦门、西安、桂林、杭州、昆明、广州（白云机场）、深圳（罗湖、皇岗、蛇口）、珠海（拱北）等地。
You should come into China with a valid visa, which can be applied from Chinese diplomatic missions abroad, consular offices, or other resident agencies authorized by the Ministry of Foreign Affairs.
外籍人士应凭有效签证入境，可向中国驻外国的外交代表机关、领事机关或者外交部授权的其它驻外机关申请办理签证。
According to your identity and the type of
your passport, the visa issued by China includes diplomatic visa, courtesy
visa, official visa and ordinary visa.
根据外籍人士来华的身份和所持护照的种类，中国所发出的签证主要包括外交签证、礼遇签证、公务签证及普通签证等。
The most common visa for businessmen is
ordinary visa. According to your reasons for coming to China, the visas are
divided into D, Z, X, F, L and other types.
商务人士最常用的是普通签证，签发部门根据外籍人士申请来中国的事由，分为Ｄ字签证、Ｚ字签证、Ｘ字签证、Ｆ字签证及Ｌ字签证等。
一、签证类型
D Visa
issued to people who want to settle in
China;
Ｄ字签证：发给来中国定居的人士
Z Visa
issued to people who work in China as well
as their accompanying family members;
Ｚ字签证：发给来中国任职或者就业的人员及其随行家属
X-1 Visa
issued to people who study, take refresher course and have internship for more than six months;
Ｘ-1字签证：发给来中国留学、进修、实习６个月以上的人士
X-2 Visa
issued to people who study, take refresher course and have internship for less than six months;
Ｘ-2字签证：发给来中国留学、进修、实习不超过６个月的人士
F Visa
issued to people who are invited to China
to have a visit, make surveys, give lectures, do business, conduct scientific
and technological cultural communication, have short-term education or
internship for less than six months;
Ｆ字签证：发给应邀来中国访问、考察、讲学、经商、进行科技文化交流及短期进修、实习等活动不超过６个月的人士
L Visa
issued to people who come to China to
travel, visit relatives, or deal with personal affairs;
Ｌ字签证：发给来中国旅游、探亲或者因其它私人事务入境的人士
G Visa
issued to people who pass through China;
Ｇ字签证：发给经中国过境的人员
C Visa
issued to international train attendants,
air crew members, seamen operating international services, and to their
accompanying family members;
Ｃ字签证：发给执行乘务、航空、航运任务的国际列车乘务员、国际航空器机组人员及国际航行船舶的海员及其随行家属
J-1 Visa
issued to resident foreign
journalists（more than 180 days);
J-1字签证：发给来中国常驻的外国记者(超过180天）
J-2 Visa
issued to foreign journalists who make a
short trip to China on reporting tasks（less than 180 days);
J-2字签证：发给临时来中国采访的外国记者(不超过180天）
M Visa
issued to people who come to China to do
business;
M字签证：发给入境进行商业贸易活动的人员
Q-1 Visa
issued to family members of Chinese
citizens for family reunion, and to family members of foreigners with permanent
residence in China;
Q-1字签证：发给因家庭团聚申请入境居留的中国公民的家庭成员和具有中国永久居留资格的外国人的家庭成员，以及因寄养等原因申请入境居留的人员
Q-2 Visa
issued to relatives of Chinese citizens
residing in China for short-term family visit, and to family members of
foreigners with permanent residence in China;
Q-2字签证：发给申请入境短期探亲的居住在中国境内的中国公民的亲属和具有中国永久居留资格的外国人的亲属
R Visa
issued to foreign high-level talents and
professionals badly needed by China;
R字签证：发给国家需要的外国高层次人才和急需紧缺专门人才
S-1 Visa
issued to the spouse, parents, children
under 18 and parents of the spouse of foreigners, who stay in China for work,
study or other reasons, for long-term family visit, and to people who need to
reside in China for other private purposes;
S-1字签证：发给申请入境长期探亲的因工作、学习等事由在中国境内居留的外国人的配偶、父母、未满18周岁的子女、配偶的父母，以及因其他私人事务需要在中国境内居留的人员
S-2 Visa
issued to family members of foreigners, who
stay in China for work, study or other reasons, for short-term family visit,
and to people who need to reside in China for other private purposes;
S-2字签证：发给申请入境短期探亲的因工作、学习等事由在中国境内停留居留的外国人的家庭成员，以及因其他私人事务需要在中国境内停留的人员
二、港澳签证
（一）香港特区签证
1、香港特区给予部分国家和地区人员免签证待遇（请点击了解详情http://www.immd.gov.hk/sc/services/hk-visas/visit-transit/visit-visa-entry-permit.html#part2 ）。
2、不享受免签证待遇的外国人赴港，须申请赴港签证。
（二） 澳门特区签证
1、澳门特区给予部分国家和地区人员免签证待遇（请点击了解详情http://www.dsi.gov.mo/documents/visa_free_macau_c.pdf ）。
2、除少数特定国家人员外，不享受免签证待遇的外国人，原则上可在澳门口岸办理落地签证。
同时申请前往中国内地、香港特区、澳门特区的外国人，须分别申请内地签证和赴港、赴澳签证。
三、有效期
签证的入境有效期（“enter before”），是指持证人所持签证入境的有效时间范围。非经签发机关注明，签证自签发之日起生效，于有效期满当日北京时间24时失效。如仍有未使用的入境次数，在有效期满前（含当日），持证人均可入境。
四、入境次数
签证的入境次数（“entries”），系指持证人在签证入境有效期内可以入境的次数。入境次数用完或入境次数未用完、但已过有效期的签证，均为失效签证。如需前往中国，须重新申请签证。如持证人持失效签证来华，将被拒绝入境。
五、停留期
签证的停留期（“duration of each stay”），系指持证人每次入境被准许停留的时限，自入境次日开始计算。
六、居留手续
外国人持D字、J1字、Q1字、S1字、X1字签证入境后，应当自入境之日起30日内向拟居留的县及以上公安机关出入境管理机构办理居留证件。
外国人持W系列外交、礼遇、公务、普通签证入境后，应当自入境之日起30日内向外交部或外交部委托的地方外事部门办理居留手续。