<p>No consumer behavior occurs in isolation, it is the joint outcome of multi-level nested factors such as information transmission in consumption situations and value shaping via social interactions. However, theories for multi-level research in consumer behavior remain extremely scarce. From a social interaction perspective under the “situation-individual” nesting framework, this study uses grounded theory to encode and analyze first-hand survey data of residents, constructing a multi-level influencing factor model of residents’ green product purchasing behavior (GPPB). The model covers situational-level (Level 1) stimulus information and information sources, as well as individual-level (Level 2) network size and relationship strength. Based on a sample of 1,029 Chinese residents, this study recorded 4,554 information acquisition and product selection instances across 12 daily necessity categories, including laundry detergent, food, and refrigerators. The results show that: (1) Level-1 predictors explain 38.2% of specific GPPB, while the Level-2 model explains 17.7% of overall GPPB.(2) At the situational level, stimulus information including price, function, certification, evaluation, and green attributes can directly or indirectly influence GPPB through perceived value; internal groups directly facilitate GPPB, whereas external stakeholder groups indirectly promote GPPB via perceived value.(3) At the individual level, social interaction significantly enhances residents’ GPPB; the promoting effect of relationship strength is higher than that of network size, in which normative influence (values and group atmosphere) and informational influence (perceived environmental risk) play mediating roles. The findings provide targeted theoretical and practical references for policymakers to optimize green product promotion strategies and improve relevant policy support systems.</p>