Abstract: High interconnected porous characteristics of poly(high internal phase emulsion) (PolyHIPE) and good biocompatibility of poly(ε-caprolactone) (PCL) were combined to create 3D porous polyester-based PolyHIPE scaffolds. First, ring opening polymerization (ROP) of ε-caprolactone (CL) or 4-methyl-ε-caprolactone (MeCL) was carried out using 1, 4-benzenedimethanol as initiator and Sn(Oct)₂ as catalyst, followed by acrylation of both hydroxyl ends. Then, Hypermer T96 was used to emulsify the dichloromethane/water mixing system to obtain high internal phase emulsion (HIPE, internal volume fraction was above 74%), where pentaerythritol tetra(3-mercaptopropionate) (PETMP) was added afterwards. Finally, under UV light irradiating, thiol-ene click cross-linking took place in continuous phase to form high interconnected porous polyester-based PolyHIPE scaffolds. The structure of PCL or poly(4-methyl-ε-caprolactone) (PMCL) and acrylation of the polymers were characterized by nuclear magnetic resonance (¹H-NMR) and gel permeation chromatography (GPC). Cross-linking conditions for PolyHIPE were also studied by scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and universal material tester to reveal the microstructure, thermodynamics and mechanical properties of the porous PolyHIPE scaffolds, respectively. Moreover, biological properties of the scaffolds were evaluated by cytotoxicity assessment and hepatocyte culture experiment in vitro. Results showed that polymerization and complete acrylation of PCL and PMCL were successfully achieved. In addition, the stability of the emulsion could be adjusted by controlling molecular weight of PCL or PMCL, water content and temperature of internal phase. Furthermore, the water temperature of HIPE had a more dominant influence on thermodynamics and mechanical properties of PolyHIPEs than the water content did. Higher water temperature of HIPE led to higher glass-transition temperature (T_g) of the scaffold, as well as lower stiffness. Soxhlet-extracted PolyHIPE scaffolds were almost non-toxic in vitro. For hepatocyte culture, the lower stiffness of scaffolds was beneficial for cell proliferation and function express.