There are two information processing in the process of individual decision making which are shown as heuristic and analytical decision strategy, the former is generally characterized as quick, automatic and affective and the latter is considered to be slow, logical and analytic in nature. These two decision strategies have their own applicable conditions, decision task characteristics (task structure, task content, how the task is presented and task complexity) can affect their effectiveness. Due to the effect of task characteristics on strategy is hotly debated, we consider that existing studies have neglected subjectivity of decision maker in the experimental operation. Different individuals may have different perception on the same task, the same characteristic may be perceived as different. This research focused on the subjectivity of decision task characteristics and examined the impact of task importance on the two decision strategies. We at first investigated the impact through field experiment in real consumption situation and then further tested the results by manipulating related variables in the laboratory. Our hypothesis was that when the task was perceived important, the effect of analytical strategy was better than heuristic strategy; when the task was perceived not important, heuristic strategy was more effective. Study 1 was implemented at the exit of campus supermarket and the subjects were college students who had just finished consuming. The investigation involved the background information of the subjects and three questions which were importance of the commodity, the strategy used to select it and the satisfaction after purchasing by self-report questionnaire. Study 2 employed a 2 (importance: important vs. unimportant) ×2 (decision strategy: heuristic vs. analytical) between-subjects design. Importance was manipulated by relevance of decision results and decision strategy by instruction both accompanied by post testing. The dependent variable was post-decision satisfaction. Participants were assigned to different conditions to finish different course selection task and a series of post testing. In this study, participants' moods were measured when they fulfilled course selection task. The results showed that task importance has impact on the effectiveness of decision strategies. When task was perceived important, the effect of analytical strategy was better than heuristic strategy and when task was perceived not important, the effect of heuristic strategy was better. In better condition post satisfaction of subjects was higher. In this study, the differences of post satisfaction which various groups showed were not due to subjects' moods. Current research can contribute to further understanding the decision makers’ perceived task characteristics as well as the relationship between which and decision strategy. This research imply that the relationship as influence on decision quality. Moreover, our findings can also help to develop the relevant theories of behavioral decision making and provide a new idea for improving individual decision quality. Future research need to examine whether this result can be reflected in other variables such as behavior and behavioral tendencies, after all, subjective evaluation in this research is the most sensitive variable.