The invention relates to a detecting method of the full spring rate of a mechanical watch. The detecting method is suitable for the mechanical watch. The mechanical watch comprises a movement, a spring winding mechanism and a spring, the spring and a handle are arranged on the movement, the handle is in transmission connection with the spring, and when the handle rotates, the energy storage springis driven to be wound for energy storage. The detecting method of the full spring rate of the spring comprises the steps that S1, the number N of rotating turns of the handle from the zero energystorage state of the spring to detecting are obtained; S3, the number N of rotating turns of the handle from the zero energy storage state of the spring to the full spring state are obtained; andS5, the first full spring rate of the spring is calculated according to the formula of eta=N/N. The detecting method of the full spring rate of the mechanical watch is suitable for the mechanical watch of any model and any structure, under the premise of not needing to demount the movement part, a calculation formula of the full spring rate can be quickly obtained in the mode of combination of detecting and calculation, thus the full spring rate of the movement under the different winding states can be evaluated, meanwhile, the detection efficiency can further be improved, the research and development costs are lowered, and the product quality is improved.