With the country's strong advocacy of green ecological civilization and sustainable development, China's consumption structure is facing the transformation and upgrading from the traditional model to the green model. In order to meet the needs of modern green consumption, enterprises have begun to continuously introduce green products and communicate with the public through green advertising, striving to stimulate consumers' green consumption motivation. However, due to the weak supervision of the quality of green advertising and the large amount of false information created by advertisers and media platforms, so that most consumers hold a wait-and-see attitude towards green advertising appeals. The issue on how to promote green marketing with effective advertising appeals has attracted great attention of business and academic circles. Based on the Cognitive Resource Matching Hypothesis, this study conducts three situational experiments to explore the matching effect between the social crowding and the advertising appeal on consumers' willingness to purchase green products, as well as the mechanism and boundary of this effect. The results of the study show that the social crowding and the advertising appeal have an interactive effect on consumers' willingness to purchase green products. Specifically, in a high-crowded social environment, the emotional appeal can better promote consumers' willingness to purchase green products whereas in low-crowded scenes, the rational appeal can better promote consumers' green product purchase intentions. Perceived diagnostic plays a mediating role in this interactive effect path and the consumer environmental involvement regulates the interactive effect. This interactive effect is only significant when the consumer environmental involvement is low. The findings of the study provide some suggestions for enterprises' green marketing practice. When carrying out green advertising marketing, enterprises should pay attention to the matching of the social crowding and the advertising appeal, and pay more attention to the role of perception diagnostic and its coping strategies. At the same time, enterprises should pay attention to the cultivation and promotion of consumers' environmental involvement, and adjust green marketing strategies by combining with consumers' environmental involvement.

Social Crowding, Advertising Appeal, Perceived Diagnostic, Environmental Involvement, Green Purchase Intention