In this study， a colorimetric biosensor based on DNA-stabilized silver nanoparticles （DNA-AgNPs） has been developed for highly sensitive detection of hydrogen peroxide and glucose levels in pear juice. DNA-AgNPs were synthesized by reduction of AgNO3 with NaBH4 under protecting of random oligonucleotide. The DNA-AgNPs has a characteristic absorption peak located at 424 nm. In the presence of hydrogen peroxide or glucose / glucose oxidase， DNA-AgNPs could be etched into smaller particles with decreasing absorbance. The solution color correspondingly changed with concentration of hydrogen peroxide or glucose， which could be directly distinguish by naked eyes. Under the optimized conditions， the limit of detection （LOD） towards hydrogen peroxide and glucose reached as low as 0.36 μmol/L and 1.13 μmol/L （S/N=3） respectively. The potential application of the developed biosensing system was evaluated with peach juice as real sample. The provided strategy could serve as a prototype for developing assays in food analysis.