The construction safety record in Hong Kong has been improving in recent years, due to a number of initiatives introduced such as Pay for Safety Scheme initiated by the government and the enhanced safety awareness of the industry practitioners. It is however found that the accident rate of the construction industry is still significantly higher than those of other industries and we are still far from claiming that the safety performance of construction industry is satisfactory. Perhaps, extension of Pay for Safety Scheme to subcontractor level would be a solution to further reduce the number of accidents in construction sector in Hong Kong. The aim of the proposed study is to scrutinize whether and how a "Pay for Safety Scheme for Subcontractors (P S S S) " could lead to better safety performance. To achieve this, the study will investigate the causal relationship between safety performance and profit on construction projects, and recommend a practical way for determining the optimum incentive level and type of P S S S for different projects. The research results would generate some valuable insights into the future development of PFSS, and facilitate the implementation of PFSS for subcontractors in near future. It is also expected to allow decision makers to have a clearer insight in determining the optimal budget of contract sum allocated for the payable safety items in tender pricing by both main contractor and subcontractor organizations at an early stage of project development, and to investigate how the site accidents can be mitigated via PFSS.