Negative longitudinal magnetoresistivity (nLMR) induced by the chiral anomaly together with the weak antilocalization (WAL) due to the quantum interference can be regarded as remarkable magnetotransport signatures for three-dimension (3D) topological semimetals. Here, we report the observation of high-temperature competition between the chiral anomaly and WAL by magnetotransport measurements on high-quality Cd3As2 nanoplates under parallel electromagnetic fields. We find that, the WAL dominates the magnetotransport in the weak magnetic fields, which decreases gradually and ultimately vanishes at a critical temperature Tc. In contrast, the chiral anomaly is robust against temperature and can survive up to room temperature. This competition between the chiral anomaly and WAL can be understood in terms of Berry phase, accompanying with the low carrier density in Cd3As2 nanoplates. Our work would offer a better understanding of magnetotransport properties governed by Berry phase and the nature of electronic states in topological semimetals.