This research want to discuss some issues about payment system of America. This research focuses on comparing ACH with Fedwire. Firstly Fedwire is the payment system for only large-dollar transfer(Large-Value Transfer System; LVTS), while ACH(Automated Clearing House)payment mainly applies a consumer account. Secondly ACH transaction is either credit or debit transfer, while Fedwire is only credit transfer. Thirdly the communication system of Fedwire has twoway method, telephonelike communication network, but ACH is oneway store and forward electronic mail. At present LVTS divides into RTGS(Real-Time Gross Settlement) and DNS(Deferred Net Settlement). However Fedwire uses either RTGS(instantaneous for every transaction) or DNS(net net transaction) but ACH uses only DNS(net net transaction). Fourthly ACH is substantially cheaper than the Fedwire payment. lastly security is important in both Fedwire and ACH, it is even more crucial in Fedwire In addition, for each transaction, Fedwire may entail individual instantaneous confirmation to the originator and notification to the receiver, whereas ACH do not.