Abstract: In the context of promoting the high-quality development of the real estate sector, timely understanding of changes in residents’ willingness to purchase housing is essential for assessing fluctuations in market demand and providing evidence-based support for policymaking by governments and real estate enterprises. Based on Baidu Search Index data at both the national and city levels, this study selects keywords that explicitly reflect housing purchase intentions and constructs a quantitative measure of the Housing Purchase Intention Index (HPII) for China as a whole and for 35 major cities. The HPII values of these cities are further categorized into three levels: high, medium, and low. In addition, the study examines the predictive power of the HPII for future housing price movements. The results reveal that China’s national HPII experienced a structural shift during the sample period, reaching its peak in 2018 and showing a downward trend thereafter. Housing purchase intentions have diffused from core coastal cities in eastern China toward selected inland cities in central and western regions as well as northeastern regions, accompanied by a substantial expansion in the number of cities exhibiting medium or low HPII levels. Moreover, the HPII demonstrates strong predictive ability for future housing price changes not only at the national level but also across different regions.