Long-term simulations using the Community Atmosphere Model (version 5.1) at low (T42), medium (T106), and high (T266) resolutions are carried out to study the impact of horizontal resolution on the model performance in reproducing the climatological features of precipitation over East Asia, where the largest differences in the modelled rainfall among three simulations are located.The simulated spatial pattern of annual mean precipitation amount improves significantly with increases in resolution.The low-resolution model is inadequate to reproduce the precipitation closely associated with fine-scale orographic forcing, such as the narrow large-rainfall belt along the southern edge of the Tibetan Plateau.The distribution of rainfall over and around the elevated plateau and lofty mountains becomes more realistic at higher resolutions as more details of topography are represented.The proportion of the large-bias (small-bias) area continuously reduces (increases) when going from T42 to T266 resolution.Simulations at all the three resolutions can capture the key features of the major seasonal variation of rainfall arising from the onset and advancement of the Asian monsoon.The hourly intensity-frequency structure is sensitive to the horizontal resolution.The percentage of light rain, which has large positive bias in climate models, decreases dramatically at higher resolution.The intensity structures averaged over steep terrain regions and plain areas become more distinctive as the resolution increases.