We report the synthesis and characterizations of Poly(ethylene glycol) (PEG) modified P2O5-CaO-SiO2 gel bioglass. Three kinds of PEG with different molecular weight (400，6 000，10 000) were used in the preparation and their influence on the nanostructure of the resultant gel bioglasses was investigated. Due to the excellent aqueous solubility and compatibility of PEG with the inorganic P2O5-CaO-SiO2 components, no phase separation was detected in the hybrid gel glasses under scanning electron microscopy (SEM) observation. FT-IR spectra indicate that hybridization between the organic and inorganic part was successfully achieved at the molecular level. SEM images and N2 adsorption-desorption experiments show that, among the three samples, S6 000 is the most promising candidate for bone scaffold material, because of its hierarchical pore structure, high porosity and surface area.