Although the light scattering technology can be used to detect the proteins in milk, there are many factors which have influence on its detection accuracy in practical use. The light scattering characteristics of the proteins in milk are analyzed. On the basis of this analysis, the Mie scattering theory and optical simulation software are used to study the factors such as laser wavelength, scattering angle and ambient temperature etc which have influence on the scattering light intensity of the proteins in milk to be detected. Through simulation, the best laser wavelength is determined to be 1333nm or 1660nm; the better scattering angles are determined to be 0°, ± 30° and ±90° and the suitable ambient temperature is from 40℃ to 60℃. This can provide the data support for the improvement of the detection accuracy of an instrument. The method does not need any actual detection instruments. Thus, it can avoid the complicated operation of a detection instrument and eliminate any artificial errors. Moreover, all parameters can be adjusted according to the requirement in experiment and the study cost can be saved.