Land shortage problem is a challenge for the future development in Hong Kong. Nowadays, reclamation and redevelopment are the major methods used to increase land supply. Yet, they are not sustainable in long term. Another environmental problem Hong Kong is facing now is the exhaustion of landfills, and therefore there is an urgent need to find a new way to solve the waste disposal issue. In order to obtain new land and solve the land exhaustion problem, the development of rock cavern has been introduced recently. Through effective planning and usage of the underground space in the rock cavern, a wide variety of facilities can be relocated or developed underground. This will release the ground surface for future developmental uses, including constructing landfills. This research aims to investigate the feasibility of underground landfill development in Hong Kong. It also aims to examine the opinion of the general public towards the rock cavern development idea. Interviews and questionnaire surveys will be conducted with both expertise and the general public, so as to investigate the practicability of underground landfills, and the interviewees’ attitudes and opinions towards the rock cavern development in Hong Kong. The development of the underground landfill will provide a new way to solve the aforesaid problem and introduces a better way for Hong Kong to increase the land supply in the pursuit of sustainable development.