This study examined the underlying types of intergenerational relationship and social support network among impaired older adults in China and explained how they may influence the home- and community-based service (HCBS) purchase intentions of these individuals. Based on the 2018 and 2020 waves of the Chinese Longitudinal Aging and Social Survey, a total of 3,397 older adults (aged ≥ 60 years, with at least one child) were selected. First, we used K-means cluster analysis to identify five types of intergenerational relationship among Chinese families: ‘tight-knit and proximal’, ‘parent-oriented and intimate’, ‘distant but intimate’, ‘independent-intimate’ and ‘child-oriented but emotionally detached’. Second, we examined the sizes of three distinct types of social support network among older Chinese adults: contact, instrumental and emotional. Subsequently, binary logistic regression was conducted to examine the relative impact of intergenerational relationships and social support networks on impaired older adults’ HCBS purchase intentions. Our findings revealed that under the moderation of social support networks, reciprocal intergenerational relationships exhibited fewer HCBS purchase intentions, while imbalanced intergenerational relationships exhibited diverse HCBS purchase intentions. The findings also underscore the ‘bridge’ function of older adults’ social support networks and the importance of community participation in promoting older adults’ utilization of support services.