Atmospheric deposition of nitrogen (N) compounds have significantly increased worldwide in the recent decades, mainly in the form of ammonium (NH₄⁺-N), nitrate (NO₃⁻-N) and urea (CO(NH₂)₂). Here, we used meta-analysis to compare the influence of different N types on terrestrial soil microbial biomass based on 1585 paired observations from 178 articles. In all N types, NH₄⁺-N addition displayed the greatest negative affects on soil microbial biomass (-18.9 %) followed by. NH₄NO₃ (-7.51 %) and NO₃⁻-N (-7.26 %). CO(NH₂)₂ addition resulted in the smallest total microbial biomass declines among all N types (-6.99 %). All the soil microbial characteristics, such as fungi and bacteria, revealed the same trends across all ecosystems, especially for arbuscular mycorrhizal fungi, F/B, and G+/G− ratio. In addition, the response sizes were significantly correlated with the accumulated N amount (N addition rate × application duration). The results indicated that the response sizes were significantly N-type dependent.