The invention belongs to the field of semiconductor nanomaterial preparation, in particular to a method for rapidly preparing spherical mercury sulfide nanoparticles, aiming at the existing problem of not being able to save energy and time, and synthesizing mercury sulfide nanoparticles with uniform shape and size and good dispersibility. Propose the following scheme, which includes the following steps: S1: Preparation of reaction mixture: at room temperature, add 0.5mmol of mercury nitrate, 0.5mmol of sulfur powder, and 0.15g of polyvinylpyrrolidone to 500g of ethylene glycol to prepare a mixture; S2: Synthesis of mercury sulfide nanoparticles: transfer the mixed solution into an oil bath filled with dimethyl silicone oil, and perform magnetic stirring to make the mixed solution react for 2 hours; S3: Separation of mercury sulfide nanoparticles: transfer the mixed solution from the bath Take it out from the pot, add an equal volume of ultrapure water and centrifuge for 15 minutes, remove the supernatant to retain the precipitate, and wash the precipitate with ultrapure water, and the precipitate will be spherical mercury sulfide nanoparticles after freeze-drying. The solvothermal synthesis system of the present invention can be used to prepare spherical nano-mercuric sulfide; the obtained spherical nano-mercuric sulfide particles have a single crystal form, good dispersibility, uniform shape and high stability; the method and process are simple, time-consuming, and the reaction temperature Low energy consumption, low cost of raw materials, easy to obtain, and conducive to industrial production.