OMG. I get the very clear impression that many people here that are giving out the advice, don't actually have much experience traveling let alone deal with the American Consulate.
First and foremost, the Consul staff have full authority to approve or decline you. There are three major things which come into play:
- regardless of what you stated on your application, they have in advance presumed you to be guilty of _______________ (wanting to work in the US and/or overstay, etc.) and that you do not have the financial motivation or family connections to want to return home. In the case where an interview was required, they were watching you in the waiting area, before you have walked up to the window. At that moment, they passed again a judgment on you, thinking that they likely will or likely will not issue the Visa. They presume that all documents presented are likely fake. You literally have a couple of minutes to impress/convince them enough to grant you the Visa.
- they have a quota (a limit) on the number of Visas that can be issued in each category.
- current politics ( in your case, the current relationship between the US and China) are a clear factor.
There is an appeal process where you contact the US State Department directly. It is very time consuming, and very rarely will they overturn the decision made by local Consul staff. The burden of proof that they clearly went against their own internal screening guidelines is on you. Since you don't know their in house rules, you have no way to prove they violating them. What you should do, if coming to the US is very important to you, is simply reapply.
When reapplying, carefully take into consideration, what you wrote before in the questionnaire, and see if there are any changes in facts that need to be made. Second, bring with you originals and/or certified copies of anything that supports your claims (traveling to foreign countries that are friendly to the US, ownership of any homes, buildings, businesses, bank statements going back a couple years, statements by employers confirming your position, responsibilities and salary, plus a statement that they are only allowing you to be absent for certain days, and that they expect you to return to your position by a certain date, etc.).
If you are willing to leave your minor children at home, while you and your spouse travel, this will improve your chances of being approved.
When given the option to speak in Mandarin, Cantonese or English, consider speaking in English. Because of the language, there is a more personal connection between you and the interviewing officer.
Dress professionally, and walk with confidence (but without attitude). Try to dress more like a wealthier educated American (whatever that means to you). Do not be afraid of the officer. Look them straight in the eyes. Do not give them the feeling that you are lying about anything. Always speak with respect but also with confidence.
The last piece of advice, try to find the fax number or email addresses to the Consul General and Consul Section. Prepare a signed letter using very good English. Introduce yourself. Let them know that you had previously applied on X date, and was denied, and was actually surprised by that decision because you were able to prove your ___________________. Perhaps it was in error or misunderstanding, and therefore you are reapplying for the Visa, and have a new interview date of X. Attach all supporting documents to the fax or email. You can even let them know that if necessary you would leave your minor child at home with relatives, to allow you to travel briefly to the US, but that you would prefer that he/she/they come with you, so that you all can visit relatives, friends, or be a tourist seeing X, Y and Z.
While officially they do not want to receive any package of documents to review in advance by email/fax, the fact is, someone likely will review it. If for any reason they want to do confirm anything (bank, title, employer, etc), they have more time to do it.
Good luck!