Abstract: The dual-process theory is an influential theory in the field of reasoning and decision-making. By analysis from the aspects of the basic characteristics, differences, and the reason of failure in reasoning and decision-making, many problems have been found on the understanding of some basic matters of this theory:(1) The key distinctions between the two systems are not the absolute participation or not of working memory;(2) Different researchers of dual-process theory differently explained the failure of reasoning and decision-making;(3) The understanding of the failure of reasoning and decision-making is awaited by the aspects of the influence and the relationship between emotion and reasoning

Key words: reasoning, dual-process theory, conflict monitor