We developed a gift exchange game with the attribute of soft corruption that can test subjects’ behaviors in acting as both a gift giver and a gift recipient. In the experiment, we use an implicit priming method to make Confucian culture values mentally salient and measure the impact on subjects’ behaviors. Additionally, we introduce the intervention of a moral reminder to test whether altering the external environment related to the scope of self-directed moral justification affects behaviors in soft corruption. We show that soft corruption is pervasive: 65.8% of subjects choose to send a gift; only 6.2% of gift recipients would reject a gift; subjects strongly reciprocate gifting behavior by awarding higher scores to gift givers. Priming Confucian culture had no significant effect on gift-giving behavior while simultaneously promoting the fairness of grading as a grader. The intervention of a moral reminder has a limited effect on the Confucian culture groups’ gift-giving behaviors and has a limited effect on the fairness of grading for the control group.