The invention provides a preparation method for a precise torsion balance, the precise torsion balance and an application method. The preparation method comprises the steps: setting a slit on a substrate; taking metal nanoparticles as catalyst, inputting the mixture of carbon source gas and inert gas into the substrate, and generating a suspended carbon nanotube on the silt of the substrate; enabling aromatic organic molecules to perform the epitaxial growth on the suspended carbon nanotube to form crystal, forming an organic rotating body on the suspended carbon nanotube, and obtaining the precise torsion balance composed of the suspended carbon nanotube and the organic rotating body. According to the scheme of the invention, the method can achieve the preparation of the torsion balance, and the precise measurement of a miniature force and torque can be achieved through the precise torsion balance.