Regret, as a post-purchase or post-decision experience, has attracted much attention because of its negative impact on consumer's well-being and post-purchase behaviors.  To reveal the occurrence mechanism of regret has important significance in reduceing consumer regret. However, existing literature is limited on the occurrence mechanism of decision regret and differences of purchase types.  Starting from types of purchase, based on decision justification theory, this paper studies how different purchase types ( material versus experiential) influence their respective regret types ( process or outcome) through decision - making styles ( analysis versus heuristic) , and investigates the influence of regulatory focus on this effect.  Three inter-group experiments show that experiential purchase brings heuristic decision - making tendency, which is more likely to produce decision process regret, while material purchase brings rational decision - making tendency, which is more likely to produce decision outcome regret.  Regulatory focus ( promotion versus prevention) moderates the relationships among purchase type, decision regrets and decision-making styles.  This study is of great significance for reducing consumers' post- purchase regret and guiding enterprises to formulate marketing strategies.