Double skin facades (DSFs) are widely recognised as sustainable design elements for reducing energy consumption in buildings. However overheating problems in DSFs in warm seasons have been reported in various studies which may cause additional increase in cooling loads in buildings. Although various thermal management strategies and devices are available, they do have some limitations and cannot be readily used for enhancing the performance of DSFs. Previous study has developed an integrated phase change material (PCM) blind system for double skin façade and has demonstrated some level of capacity to mitigate the overheating phenomenon in DSF. This paper focuses on the optimisation of such integrated PCM blind systems for DSF buildings by conducting simulation study. The numerical models were validated with experimental data in a DSF test facility integrated with the developed prototype. Temperature and heat flux profiles in the DSF integrated with the PCM blind with different positions in cavity and vertical inclinations of blades were simulated and compared by using computational fluid dynamics (CFD) method. An analysis of different properties of PCM was also carried out in consideration of the effects of various types of PCM for applying in different climatic regions. As a result, the air temperature in DSF cavity can be stabilised below 38°C in warm seasons in terms of proper combinations of factors including position in cavity, blade tilt angle, PCM type, and direction. The performance of the current integrated PCM blind system can be optimised by carefully designing the geometry of the system and improving the energy storage efficiency of the PCM. Nevertheless, further experimental investigation and comparison should be conducted in future study.