Uncertainty is traditionally regarded as an aversive state that evokes avoidance and cognitive strain. However, recent psychological and neuroscientific findings suggest that uncertainty may also elicit approach-oriented responses under specific conditions. This study explores the paradoxical motivational effects of uncertainty through two complementary experiments. In Study 1, a behavioral gambling task examined how different levels of uncertainty influenced participants’ choices and emotional experiences. The results revealed that intermediate uncertainty was associated with increased approach motivation and enhanced positive emotional ratings. Study 2 employed event-related potentials (ERPs) to investigate the neural mechanisms underlying this effect. Specifically, greater P300 amplitudes were observed under moderate uncertainty conditions, reflecting increased attentional engagement and motivational salience. These findings challenge the uniformly negative interpretation of uncertainty, revealing its capacity to promote exploratory behavior and adaptive decision-making. The study advances a more nuanced understanding of how uncertainty modulates emotion, attention, and action readiness.