Since the resumption of customs between Hong Kong and the Mainland, exchanges between the two places have become increasingly close. With the stabilisation of connectivity between the two places and the recovery of the Mainland economy, the transaction volume of Hong Kong's real estate market has been rising. This paper compares and analyzes the real estate development in Hong Kong and the mainland, on the one hand, analyzes the real estate development history of the two places, in particular, focuses on the impact of key historical events and policies on Hong Kong's real estate, and on the other hand, compares the development status of real estate in the two places in recent years, so as to understand the characteristics and development trends of the real estate markets in the two places, and provides reference for policy formulation and investment decision-making in the context of the close connection between the real estate in the two places after the reopening of the border. At the same time, it looks forward to the development trend of real estate in Hong Kong and mainland China, predicts possible challenges and opportunities, and puts forward reasonable policy suggestions and coping strategies. The results of the study show that the development of real estate in the Mainland is more affected by the political environment and is different from that of Hong Kong in terms of economy, policy and society; the lack of land supply has become an inevitable trend in both places, and it is necessary to solve the problem in a multi-faceted manner.