The invention provides an electronic certificate installment buying processing method and system, and the method comprises the steps: enabling a first electronic certificate corresponding to a commodity to be transmitted to a buying terminal; recording bought information in the first electronic certificate when the information that the buying terminal buys the first electronic certificate in a mode of installment; sequentially judging whether to carry out payment in each period according to a payment condition or not, completing the transaction if the payment is carried out in each period according to the payment condition, recording the transaction completing information in the first electronic certificate if the payment, recording the information that the payment is not carried out according to the payment condition if the payment in any period is not carried out according to the payment condition, and generating an instruction for processing the commodity corresponding to the first electronic certificate. According to the embodiment of the invention, the first electronic certificate is bought in a mode of installment, and the first electronic certificate records the corresponding information. When the payment is not carried out timely, each side is notified for processing, and the processing result is recorded, thereby facilitating the subsequent circulation of the commodity. The method has the anti-counterfeit and source-tracking effects.