Atmospheric deposition in contact with the canopy plays a vital role in altering actual deposition to the forest floor by canopy exchange (CE; canopy uptake, CU or canopy leaching, CL) and washout of dry deposition (DD) in forest ecosystems. However, the effects of urban site characteristics on CE and DD remain less understood. Here, we examined the concentrations and fluxes of nitrogen (NH₄–N and NO₃–N), sulfate (SO₄–S) and base cations (K⁺, Ca²⁺, Mg²⁺, and Na⁺) in bulk deposition (BD) and throughfall (TF) in an urban lucidophyllous forest site (Castanopsis cuspidata), in order to clarify the characteristics of atmospheric deposition. Results showed that volume weighted mean concentrations of ions and cations were significantly higher in TF than in BD. Based on the canopy budget model, the CL of K⁺ and Mg²⁺ was the dominant contribution in the net TF (TF–BD) (86% and 80%), whereas the DD was the dominant contribution for Ca²⁺ (71%). DD of NH₄–N, NO₃–N and SO₄–S contributed 90%, 52%, and 26% of total deposition, respectively. This study can provide insights into canopy modification of base cations and acid deposition to the urban forest floor.