Yule-Nielsen spectral neugebauer (YNSN) model is widely used in printing for predicting dot area. The model’s accuracy is effected by the paper’s performance, ink kinds, wavelengths, and printing conditions. In the paper, the relation between the solid color patch’s spectral reflectance and the printing’s dark dot area is discussed. By experiments, the solid color patch’s spectral reflectance is adopted as fixed index of YNSN model, which can reduce the deviation of the dark color patch. The research has a certain significance for controlling printing quality and reducing the producing cost.