Abstract: The present invention relates to a discount service system and method according to a discount condition which defers the payment in accordance with the coupon purchase of a buyer, and changes the payment to a discount condition related with the coupon usage at the time of performing the payment to process the payment amount. According to the present invention, a payment procedure of the coupon purchased by the buyer is deferred later than the coupon used time or coupon usage and various discount conditions is set to apply additional benefit in accordance with the coupon usage of the seller to provide a discount in accordance with a discount condition in connection with the coupon usage of the buyer, to guide the buyer to use a coupon in a seller's desired direction, thereby maximizing the benefit of the seller.