Mountings of studies discussed about a variety of antecedent factors of risky decision making, however, loneliness, as a vital psychological state featured by affection, cognition as well as behavior, was seldom connected to risky decision-making. The current study aims to figure out whether loneliness would influence decision making under risks and the possible underlying mechanism. Two hundred and fifty participants attended our studies and completed gambling games via either pen-paper or E-Prime software. The results indicate that higher level of loneliness predicts less perceived self-control, which in turn leads to a tendency to avoid risks. However, this effect is only significant in gain scenarios rather than loss scenarios, suggesting there might exist an interaction between loneliness and condition factor. Our findings contribute to previous research by verifying that the preventive focused mind-set of loners can go beyond social events and influences decision making behaviors.