I find the following from the Website of US Consulate in Shenyang:
http://shenyang.usembassy-china.org.cn/faq2/applying-for-the-visa2.html
Who can accompany an applicant to his/her visa interview?
The applicant is the only person allowed into the U.S. Consulate for a visa interview. Relatives, friends, co-workers, employers, lawyers, etc. will not be allowed into the building. However, parents or legal guardians are permitted to accompany any minor child (age 17 and under) to an appointment if the child is applying for a tourist visa.
Children under age 14 do not have to appear in person, unless they are applying for a student visa. If the minor child is not present, a parent or legal guardian can apply for a tourist visa on behalf of that child. Parents or legal guardians must provide proof of relationship or legal guardianship status, such as an original birth certificate or other court documents. Please note that applicants for student visas (F/J/M) that are under age 14 must come to the U.S. Consulate in person to be interviewed.
