The last decades have witnessed the resurgence of research on linguistic relativity, which provides empirical evidence of possible language effects on thought across various perceptual domains. This study investigated the linguistic relativity hypothesis in the abstract domain of time by looking at how L1 Chinese - L2 English bilinguals conceptualize time in two-dimensional space. English primarily relies on horizontal spatial items to talk about time (e.g., back to youth); in addition to horizontal spatial metaphors (e.g., ‘front year’), Chinese speakers also commonly use vertical metaphors to describe time (e.g., ‘up week’). If language has an effect on thought, then spatial-temporal metaphors should shape people’s temporal cognition. In this study, we examined whether spatial-temporal metaphors impact online processing of time and long-term habitual thinking about time. Experiment 1 showed that bilinguals could automatically access the timeline which corresponded to the immediate linguistic context. In Experiment 2, a majority of bilinguals demonstrated salient vertical bias for temporal reasoning, whereas a small number of participants relied on the horizontal axis to represent time. The dominant thinking patterns for time documented here (65% prefer a vertical representation of time; 35% horizontal) run counter to the fact that horizontal metaphors are twice as common in Chinese as vertical metaphors. Further, it was found that bilinguals who used English more frequently were more likely to have a less vertical bias, which suggested a role of L2 experience in conceptual representations. Taken together, the evidence in this study showed that spatial-temporal metaphors have both short-term and long-term effects on mental representations of time, but also that space-time mappings do not depend solely on linguistic factors.