Speakers of Mandarin Chinese are thought to conceptualise time along the vertical axis—as evidence for metaphor embodiment—but the extant behavioural evidence remains unclear. Here, we used electrophysiology to test space–time conceptual relationships implicitly in native speakers of Chinese. We employed a modified arrow flanker task, in which the central arrow in a set of three was replaced by a spatial word (e.g., 上–‘up’), a spatiotemporal metaphor (e. g., 上个月–‘last month’, literally ‘up month’) or a non-spatial temporal expression (e.g., 去年 –‘last year’, literally ‘gone year’). N400 modulations of event-related brain potentials served to measure the level of perceived congruency between semantic word content and arrow direction. Critically, we tested whether N400 modulations expected for spatial words and spatial temporal metaphors would generalise to non-spatial temporal expressions. In addition to the predicted N400 effects, we found a congruency effect of a similar magnitude for non-spatial temporal metaphors. On the basis of direct brain measurements indexing semantic processing, and in the absence of contrastive behavioural patterns, we demonstrate that native speakers of Chinese conceptualise time along the vertical axis, and thus have embodied spatiotemporal metaphors.