Old trees as a natural heritage are significant components of terrestrial biodiversity, and they also play an important role in the ecosystem. An overall understanding of the distribution patterns and ecological characteristics of old trees in China’s Anhui Province will provide valuable insights into old tree conservation and scientific planning. Based on the data from 617 field collection and historical sample documents, we applied DIVA-GIS combined with the BIOCLIM model to qualitatively and quantitatively analyse the distribution patterns of old trees and their dominant climate factors for the first time. The model assessment results indicated that the area under the receiving operator curve (AUC) and kappa statistics reached 0.969 and 0.921, respectively, which indicated that the data fit the model very well and that the prediction was highly reliable. According to principal component analysis (PCA), the main bioclimatic variables influencing the distribution of old trees were as follows: water requirements, drought tolerance, preference temperature, heat resistance, cold tolerance and others. The cumulative frequency curves further confirmed that the ecological characteristics of the geographical distributing area for old trees in the study area were annual mean temperature (10.90~16.30ºC), maximum temperature of warmest month (25.60~32.40ºC), mean temperature of coldest quarter (0.30~4.90ºC), annual precipitation (665.00~1701.00 mm), precipitation of driest month (14.00~47.00 mm) and precipitation of driest quarter (45.00~173.00 mm). The current distribution pattern of old trees was mainly affected by precipitation factors. Furthermore, this study demonstrates a new method for the conservation of old trees by virtue of GIS software and predictive models. All of these results could help establish conservation plans for old trees.