Abstract: An apparatus and a method for continuous solvothermal synthesis of nanoparticles, are provided. The apparatus includes an inlet section, a reactor section, a flexible quenching unit, and an outlet section. The inlet section separately receives reactants including the solvent and a precursor solution that are allowed to flow into the reactor section. The reactor section includes multiple spiral turns such that each of the spiral turns includes a helical channel followed by a counter-helical channel for enabling mixing of the reactants to cause solvothermal reactions between them. The counter-helical channel changes the direction of flow of reactants upon flow of said reactants from the helical channel to the counter-helical channel. The flexible quenching section enclosing a portion of the reactor section quenches a slurry formed as a result of the solvothermal reactions, wherein the slurry includes the nanoparticles of targeted characteristics. The outlet section facilitates withdrawal of the slurry.