Au@ SiO2 nanocomposite was prepared. A novel DNA electrochemical sensor was fabricated by coating Au@ SiO2 nanocomposite on glass carbon electrode and subsequently by immobilizing DNA probe on the modified electrode. The electrochemical behavior of the nanocomposite film was investigated by cyclic voltametry and different pulse voltametry(DPV). The experimental conditions including the immobilized temperature,immobilized time,hybridization temperature,and hybridization time were optimized using [Fe(CN)6]3- ...