Abstract: As China's imported cross-border e-commerce has entered a stage of rapid development, the problem of consumer shopping risk is increasingly prominent and the crisis of consumer trust is intensified. The theory of building consumer trust in traditional online shopping can no longer meet the needs of cross-border scenarios. This paper adopt the methods of network logs and grounded theory. The data collection and analysis are conducted on consumer reviews from Tmall international, Netease koala and JD global shopping in the commodity review area. This paper explores and extracts the moderating variables of consumer perceived risk and cross-border characteristics in cross-border e-commerce. Based on the theory of "perceived risk-consumer trust-consumer purchase decision-making", this paper deduced mechanism of consumer dynamic trust based on the whole process of cross-border e-commerce transaction. It is concluded that in the pre-purchase, purchase and post-purchase stages of cross-border e-commerce transactions, consumers' perceived cognitive risk, transaction risk and utility risk are moderated by the cultural distance, geographical distance and institutional distance caused by the cross-border transaction subjects. On this basis, the pre-influence factors of trust in each transaction stage are synthesized to respectively influence the establishment of cognitive trust, emotional trust and behavioral trust, so as to affect consumers to make the order payment, confirm receipt and praise repurchase decisions. At the same time, with the advance of pre-purchase, purchase and post-purchase transactions in cross-border online shopping, consumer trust presents a dynamic evolutionary path of "cognitive trust-emotional trust-behavioral trust". Finally, based on the conclusion of this study, three suggestions are put forward for the construction of consumer dynamic trust in import cross-border e-commerce platform, namely establishing cross-border e-commerce websites with the national characteristics as the main line of commodity display and search, increasing the national or regional consumer evaluation system, and establishing a customer service response team of cross-border e-commerce platform with national characteristics.

Key words: Import cross-border e-commerce, consumers' dynamic trust, grounded theory, cultural distance, geographical distance, institutional distance