申请非移民签证之前，签证申请人，包括儿童在内，均需缴纳签证申请费，并且该费用不予退款、不得转让，有时也称为可机读签证(MRV)申请费。无论是否获得签证，均须缴纳签证申请费。具体费用视申请的签证类型而定。根据您的国籍及所申请的签证类型，您可能还需缴纳签证签发费或“对等”费。https://www.ustraveldocs.com/cn_zh/cn-niv-visafeeinfo.asp

Visa applicants, including children, are required to pay a non-refundable, non-transferable visa application fee, sometimes referred to as the MRV fee, before applying for a nonimmigrant visa. The visa application fee must be paid whether a visa is issued or not. The type of visa for which you apply determines the fee amount. Depending on your citizenship and the type of visa you are applying for, you may also have to pay a visa issuance or “reciprocity” fee.

来源：2017-05-09美国驻华大使馆美国驻华大使馆