System for complex payment processing and method therefor

The present invention relates to a system for complex payment processing, which enables payment processing simultaneously using a payment means such as a credit card and a discount means such as a discount coupon, and a method therefor. Specifically, the present invention provides a system for complex payment processing, wherein if a complex payment is requested by a user, the system generates and provides optimal complex payment information by checking a payment means or a discount means, and if a modification to the provided complex payment information is requested, the system promptly provides the modified complex payment information and information about a payment amount without accessing a server.