With the increasing application of biosensors, the development of new biosensors has become an important strategy for the development of science and technology in the world. Scientists have cross-infiltrated nanotechnology and biotechnology to form nanobiotechnology, and develop nanobiosensors. Compared with traditional biosensors, due to the enhanced electron transfer kinetics and strong adsorption capacity of nanomaterials, it provides higher stability for bioelectrodes, high surface-to-volume ratio for higher biomolecule loading, and a high level of stability for the bioelectrode. Biomolecules including enzymes, antibodies, microorganisms, DNA and other proteins can be immobilized to provide a suitable microenvironment. Therefore, nanomaterials can not only greatly improve the detection sensitivity of the sensor, but also provide a theoretical basis for the analysis of single molecule activity. The combination of nano and biology can also improve clinical efficacy and improve biological species, which can be used for microbial detection, monitoring of body fluids metabolites, and early detection of tissue lesions such as tumors. As a direct wide-bandgap semiconductor, ZnO has been used in electronic devices, optoelectronic devices, biosensors and other fields due to its excellent properties such as non-toxicity, good biocompatibility, stable physical and chemical properties, and it can take advantage of its high isoelectric point to bind and immobilize biomolecules with low isoelectric points such as proteins through electrostatic adsorption interactions. In particular, the research of biosensors based on nano-ZnO has become a new hot spot in the field of epidemic prevention and medical treatment. In this paper, we introduce several main preparation methods of nano-ZnO (including hydrothermal method, magnetron sputtering method, sol-gel method and atomic layer deposition method, etc.), their advantages and disadvantages, the excellent properties of the as-prepared ZnOs and the methods to enhance their properties (such as process optimization, doping, recombination, heterojunction, etc.) are comparatively analyzed. The article focuses on the application of nano-ZnO materials in the field of biosensors. The various unique advantages of ZnO nanomaterials enable different types of biomolecules to be successfully immobilized on their surfaces, so they have broad application prospects in the field of biosensors. The analytes most commonly used as detection materials include: lower molecular weight molecules(dopamine, uric acid, urea, and riboflavin), proteins(bovine serum albumin, immunoglobulin, streptavidin), nucleic acids(RNA, DNA), cells(cancer cells, infected cells), bacteria and many more. According to the different working principles of their signal processing components, the biosensors prepared by ZnO nanomaterials are divided into electrochemical sensors, optical sensors and field effect transistor sensors, and the use of new technologies such as piezoelectric ZnO nanobiosensors, ZnO biosensors chip and so on. Then the chitosan film is formed and fixed on the glassy carbon electrode. The hydrogen ion concentration index electrode is an electrochemical sensor widely used in blood glucose meters. The glucose sensing of vertically grown ZnO nanorods combined with chitosan is investigated. And we introduce their structures, working principles and their outstanding performance and development status for biological detection in detail respectively. Finally, we prospect and summarize the current challenges and future development trends of nano-ZnO biosensors.