In a context of increasing US-China competition, under what conditions will the Chinese hawkish attitudes towards the US be activated? This question is important for not only the US-China relations but also the dynamics concerning power transition and state conflicts. By a large-scaled survey experiment, we first test two commonly referenced explanations, dissatisfaction with status quo and nationalism, however, both are not borne out. We then raise a third causal pathway, expected short/long-time power transition (time-horizon). The results show that, contrary to the conventional wisdom, expected short-time power transition considerably mitigates the Chinese support for hawkish policy towards the US but long-time transition increases it. The effect is more pronounced in economic than security conflict settings. Mediation analysis shows this is attributable to the effect of time horizon on risk attitude, as time horizon systematically distorts public evaluations of expected utility values and success rates of aggressions towards the US.