In order to research the feasibility of staining method in measuring the acoustic field intensity, we study the mechanism that dye spots could appear on coated paper in methylene blue solution under ultrasonic condition. The dyeing mechanism was analyzed and pointed out the dye pits evolution process on the basis of the structure of coated paper,and then the experiment was carried out to test the validation. The result indicates that the theory is rational. And we can also draw the conclusion that staining method have many barriers in pullulating to a utility technology to evaluate the acoustic field quantitatively, but it is simple and easy operating in special acoustic field which requires less accuracy.