Nanomaterials have great application prospect in biological medicine due to their strong permeability, repair and regeneration. In particular, nano silver has excellent antibacterial ability and no toxic effect, which makes it widely used. The specific content of this paper introduces a method of using silver nanoparticles to generate silver ions, and then make it react with hydrogen peroxide, through the colorimetric device to react with different color changes corresponding to different concentrations, through this biosensor to determine the concentration of such as cholesterol lactic acid and other substances.And when detecting miRNA,AuNPs were further modified by complementing the DNA (cDNA) of target mirnas. AgNPs could not be attracted to negatively charged DNA due to electrostatic repulsion by immobilized modified gold nanoparticles on the electrode surface. After analyzing the peak of silver stripping, miRNA can be accurately detected.Furthermore, chitosan coated silver nanoparticles were designed, and polyethylene glycol was used as a stabilizer. Finally, its good blood compatibility and antibacterial ability, as well as its cytotoxicity to cervical cancer cells were demonstrated by characterization.Finally, the accumulation and changes of reactive oxygen species (ROS) and reactive nitrogen (RNS) induced by silver nano are introduced, and it is confirmed by measurement that they are important factors in apoptosis of human pancreatic ductal adenocarcinoma.