The invention provides a high-efficiency non-fluorescence lubricating agent for well drilling liquid and a preparation method thereof. Synthetic base oil is used as a main raw material of the non-fluorescence lubricating agent. The non-fluorescence lubricating agent comprises the following components in parts by weight: 95-98 parts of synthetic base oil, 0.5-1 part of high-efficiency extreme pressure additive and 0.8-1.5 parts of surface modified nanometer material. The preparation method comprises the following steps: taking the synthetic base oil, the high-efficiency extreme pressure additive and the surface modified nanometer material in parts by weight, adding the synthetic base oil to a container, stirring, heating, and adding the high-efficiency extreme pressure additive while stirring; stopping stirring, then adding the surface modified nanometer material to the container, continuously stirring and heating, thus obtaining the liquid lubricating agent finished product which can freely flow. The non-fluorescence lubricating agent has the advantages of relatively good adsorptivity, abrasion-resistance extreme pressure-resistance capacity, no toxicity, no fluorescence and relatively good compatibility with the drilling liquid and the like, does not interfere with geological logging and has no influence on discovery of new oil layers.