A new type of sol-gel/organic hybrid composite film based on chitosan(CS) with methytrimethoxysilane(MTOS) was developed for the fabrication of an amperometric glucose biosensor. The hybrid composite film was used to immobilize glucose oxidase(GOD) on the surface of Prussian Blue(PB)-modified glass carbon electrode. Effects of some experimental conditions such as pH, temperature and applied potential etc. on the current response of the biosensor were investigated. The biosensor has a fast response less than 10 s and linear calibration range from 5.0×10 -6 to 2.4×10 -3 mol/L with detection limit of 1.0×10 -6 mol/L. The apparent Michaelis-Menten constant K m is found to be 3.2×10 -3 mol/L. The activation energy for enzymatic reaction is calculated to be 21.9 kJ/mol. The biosensor has a high sensitivity(420 μA·mol -1·L), long-term stability and good selectivity. This method has been used to determine the content of glucose in the real blood samples.