Under the background of China’s strong promotion of sharing economy and value co-creation, traditional unilateral corporate social responsibility is transforming into co-created social responsibility with the help of charity crowdfunding platform. Online sharing is an important way through which consumers participate in co-created social responsibility. In order to clarify the motivation and cognitive mechanism of online sharing by consumers in the context of Chinese culture, the paper starts from practical examples, and adopts the interdisciplinary paradigm to construct a dual moderated mediation model. The results of quasi-experiment show that, the stronger the hope emotion aroused by charity projects, the stronger the consumers’ online sharing intention. In terms of cognitive mechanism, hope emotion can enhance online sharing intention by promoting self-actualization and response efficacy. In terms of cultural context, the effect of hope emotion on strengthening online sharing intention through enhancing self-actualization is stronger when collectivism orientation is higher. Alternatively, the effect of hope emotion on strengthening online sharing intention through enhancing response efficacy is stronger when uncertainty avoidance orientation is higher. The conclusion reveals that hope emotion arousing is an effective co-created social responsibility communication strategy. Moreover, enterprises can consider the cognitive mechanisms and corresponding cultural contexts to build an indigenized and benign co-created social responsibility model to help consumers to service public welfare and improve the social governance system.