World soils are subjected to a number of anthropogenic global change factors. Although many previousstudies contributed to understand how single global change factors affect soil properties, there have beenfew studies aimed at understanding how two naturally co-occurring global change drivers, nitrogen (N)deposition and increased precipitation, affect critical soil properties. In addition, most atmospheric Ndeposition and precipitation increase studies have been simulated by directly adding N solution or waterto the forest flfloor, and thus largely neglect some key canopy processes in natural conditions. Theseprevious studies, therefore, may not realistically simulate natural atmospheric N deposition and pre cipitation increase in forest ecosystems. In a fifield experiment, we used novel canopy applications toinvestigate the effects of N deposition, increased precipitation, and their combination on soil chemicalproperties and the microbial community in a temperate deciduous forest. We found that both soilchemistry and microorganisms were sensitive to these global change factors, especially when they weresimultaneously applied. These effects were evident within 2 years of treatment initiation. Canopy Ndeposition immediately accelerated soil acidifification, base cation depletion, and toxic metal accumula tion. Although increased precipitation only promoted base cation leaching, this exacerbated the effects ofN deposition. Increased precipitation decreased soil fungal biomass, possible due to wetting/re-dryingstress or to the depletion of Na. When N deposition and increased precipitation occurred together, soilgram-negative bacteria decreased signifificantly, and the community structure of soil bacteria was altered.The reduction of gram-negative bacterial biomass was closely linked to the accumulation of the toxicmetals Al and Fe. These results suggested that short-term responses in soil cations following N depo sition and increased precipitation could change microbial biomass and community structure.