Abstract: A payment system on network provides a platform based on the existing various transaction modes so that the current transaction modes can be operated on the secure payment platform which the present invention provides. The current transaction modes has the following kinds: a free process mode of the acquirer institution, a direct authentication mode of the card issuing institution, a secure input mode of the bank union and the other patent mode which the bank applies. The secure payment system can solve the technology disadvantage that the existing transaction flow is disorder and the resource is waste. The method of the present invention not only can be realized and its security is high, but also can achieve the less consumed time and the high transaction success using the existing private network.