With the in-depth development of economic globalization and the increasingly close ties between countries in the world, how to train international talents has become an important topic. Cross-cultural learning is conducive to broadening the horizons of learners and cultivating international talents. An effective network support environment and the design of cross-cultural learning activities are the keys to the success of crosscultural learning. As an emerging network software with rich functions, simple development and convenient use, the WeChat Mini Program (WMP) can serve as a network support platform for cross-cultural learning activities. This study developed a cross-cultural learning platform based on the WeChat mini program. Under the guidance of activity theory, this study builds a WMP-based design model of cross-cultural learning activities, including the components of learners, resources, cross-cultural learning community, WMP, rules, role division and activity process. Under the guidance of this model, we designed, implemented and evaluated WMP-based cross-cultural learning activities for Chinese students and international students at Lanzhou University. The research results show that the cross-cultural learning activities designed and implemented under the guidance of the model have a positive impact on learners' knowledge, abilities and literacies. It is expected that this study will enrich the platform of cross-cultural learning and provide a reference for the design of cross-cultural activities.