Abstract: Community group-buying is an indispensable and important model in the field of agricultural products e-commerce. In community group buying, the accumulation of social capital is evident in consumer communication and interaction, trust in the group buying initiator, the establishment of cooperative relationships, and the formation of social networks within the community. This study utilized social capital theory and consumer behavior theory, along with consumer survey data, to analyze the impacts of social capital on consumers’ willingness and behavior to purchase fresh agricultural products with group in community. Results demonstrated that the presence of social capital could enhance consumers’ willingness to buy fresh agricultural products with group in community and promote the occurrence of group buying behavior. Core variables of social capital, including whether acquaintances participate in group buying, whether someone recommends community group buying, and the level of trust in the group buying initiator, had a significantly positive influence consumers’ intentions and behaviors in group buying. Finally, the paper offered several suggestions: selecting suitable initiators in the community group buying, enhancing the reputation and service quality of both initiators and platforms, and emphasizing the impact of reference groups on consumers.