Amphiphilic hydrogels composed of aliphatic polyesters and poly(ethylene glycol) have potential applications in drug delivery, tissue engineering and other biomedical devices due to their advantageous biological properties, biocompatibility and biodegradability. However, they also exhibit some shortcomings in terms of their reactivity, swelling and mechanical properties. To address these limitations, new semi-interpenetrating network (semi-IPN) hydrogels based on poly(ethylene glycol)-co-poly(epsilon-caprolactone) (PEG-PCL) diacrylate macromer and hydroxypropyl guar gum (HPGG) were prepared by a low intensity ultraviolet (UV) light irradiation method, and characterized by FT-IR, DSC and WAXD analysis. Their properties were evaluated by investigating the swelling kinetics, dynamic mechanical rheology and the release behavior for bovine serum albumin (BSA). It was found that the introduction of the semi-IPN structure and HPGG decreased the crystallinity of PEG segments in the hydrogel, and improved the swelling and mechanical properties of the hydrogel, as well as lowered the release percentage of BSA from the hydrogel. Such hydrogel materials may have more advantages as a potentially interesting platform for the design of medical devices.The elastic modulus (G') and viscous modulus (G'') as a function of frequency for various hydrogel samples.