Anthropogenic warming may impact mean and extreme precipitation trends by enhancing the water cycle, potentially bringing threats to human societies. The design of national-level policy for disaster prevention and mitigation depends on the reliable detection of anthropogenic forcing in mean and extreme precipitation changes there. The anthropogenic signal might be obscured by strong internal variability at a regional scale. The goal of this study is to investigate the emergence of anthropogenic signal in mean and extreme precipitation trends across China by using two large ensembles (CanESM2-LE and Community Earth System Model (CESM)-LE) of simulations during 1961–2010. Results show that the signal could not be detected in either mean or extreme precipitation trend during the current climate period (1961–2010). Following the RCP8.5 scenario, the signal is projected to emerge in mean precipitation around the 2020s and 2030s in the CanESM2-LE and CESM-LE, respectively, much earlier than in extreme precipitation. For extreme precipitation, the signal could be steadily detected no earlier than the 2030s for CanESM2-LE and the 2040s for CESM-LE. These projected times of emergence in precipitation changes highlight the urgency of preparing for an uncharted hydrological future dominated by anthropogenic warming.