Abstract：Suiyuan is a newly-emerged setting that has been applied in several online fundraising platforms. Users press a button of “Suiyuan”, then the system will generate a random number such as ¥2 or ¥8 for the user to donate. Although practitioners may believe Suiyuan can increase donations, this research showed that it actually reduced charitable giving. Suiyuan diminishes people’s sense of control, which in turn reduces giving. Moreover, the negative effect of Suiyuan on giving is greater for those users with strong desire for control. This research shed light on current fundraising practices.