In this study, semi-interpenetrating polymer networks (semi-IPNs) based on chitosan and poly(2-hydroxyethyl methacrylate) (CS/PHEMA) are successfully fabricated through free radical polymerization of HEMA in the presence of CS solution with potassium persulfate (KPS) as an initiator and triethylene glycol dimethacrylate (TEGDMA) as a crosslinking agent, aiming to develop semi-IPNs CS/PHEMA structure properties by different feed ratios of CS/HEMA and TEGDMA. The resulting semi-IPNs CS/PHEMA structure shows the presence of the two polymeric components in the polymer structure. The crosslinking results in the morphological structure, high porosity and pore structure, as well as interconnected pores on the surface, indicating that a semi-IPNs hydrogel structure formed after polymerization. Moreover, the degree of swelling is excellent in different media ranging from 140 to 220%. The semi-IPNs CS/PHEMA samples exhibit highly enhanced mechanical strength with crosslinking and show features of brittle materials in the dry state and rubber-like materials in the wet state. Compressive structure exhibits retaining after stress removal. The polymeric decomposition occurs, corresponding to linear CS and PHEMA networks. The degradation behavior of semi-IPNs CS/PHEMA promotes enzymatic biodegradation under simulated physiological conditions. Therefore, these CS/PHEMA semi-IPNs materials can be suitable for use as biodegradable polymers and engineering scaffold materials.