Allamah Misbah Yazdi was the spearhead of confronting doubts both before and after the Islamic revolution. Many of these doubts have entered the cultural atmosphere of the country from the field of humanities, so he paid serious attention to these sciences. He is one of the thinkers who had a scholarly approach and far from extremes when dealing with imported thoughts and doubts. His encounter with imported doubts and thoughts is based on a specific pattern. This pattern can be explained in two areas: scientific principles and moral principles. In this article, which is organized by library method (in information collection procedure) and descriptive analytical method (in data analysis), the scientific and ethical principles of this method have been examined and introduced. The findings of this research show that emphasizing the main issues and avoiding minor ones, studying humanities and doubts as a coherent whole, presenting a positive and productive attitude, accurately describing the point of contention in intellectual disputes, paying attention to the relationship between opinion and action, the genealogical approach to materialistic thoughts and the distinction between motivation and inspiration are his most important “scientific principles” in answering doubts. Also, avoiding prejudice, respecting scientific fairness and humility, speaking softly and not being afraid of criticizing the opponents are among his “moral principles”.