Since the outbreak of COVID-19, the cross-border e-commerce platform has been rising rapidly because of its unique advantages. However, with the widespread application of information technologies such as mobile Internet and big data, fundamental changes have taken place in consumer preferences, consumption patterns, and marketing channels in cross-border e-commerce platforms. They also change the logic of value co-creation (VCC). The platform can achieve survive, expansion, and sustainable development by realising the value co-creation of the whole platform ecosystem. Based on the perspective of the platform ecosystem, this paper uses the grounded theory analysis method and NVivo 11.0 software carries out three-level coding on the obtained original data, and finally summarises and extracts four core categories of value co-creation mechanism: connection and interaction of value co-creators, demand mining, resource integration, and system support. The first two categories reflect stakeholders’ internal connection and interaction mechanism, and the last two categories reflect the external support mechanism in value co-creation.