The invention relates to a preparation method for a nanometer sizing agent for electrode printing. The synthetic steps of the nanometer sizing agent comprise preparation and synthesis of a silver nanowire solution, preparation of Prussian blue synthesis liquid A and B and synthesis, centrifugation, drying and the like of Prussian blue in the silver nanowire solution. The prepared nanometer sizing agent can be printed into electrode chips through a screen printing technique. By means of the electrode chips prepared through the nanometer composite sizing agent, precise detection of biomass in clinical medicines, food safety, the fermentation industry and bioengineering can be achieved. The synthetic process of the nanometer sizing agent is simple, the cost is low, and the nanometer sizing agent has good large-scale production prospects.