Over the last few decades, policy changes have resulted in changes in family structure and cyclical changes within families. The structure of multi-child families will have a significant influence on housing demand and supply, necessitating a thorough demand study. This study examines the requirements of 739 multi-child families in the Yangtze River Delta (YRD) region at different stages and graphically displays the variables influencing their level of housing satisfaction, offering a scientific reference for the design and optimization of housing. Firstly, the residential elements that impact families with multiple children were categorized into 3 categories, 14 subcategories, and 65 influencing elements based on expert consultation and word frequency data. Secondly, 739 families in the YRD region were chosen for investigation, and importance–performance analysis (IPA) was employed to study and assess the residential elements of multi-child families. The IPA study findings were compared to those obtained from on-site surveys and network data crawling. Finally, the residential elements to be optimized were quantitatively determined, and the relevant optimization techniques were provided in conjunction with door-to-door interviewing. This study examines the needs of multi-child families at various phases, as well as the factors that impact their residential satisfaction, and provides optimization solutions for the long-term use and renewal of residential structures.