Litter quality and soil organisms influence the decomposition process of organic matter. Although these two factors may have a synergistic effect, the role of soil fauna in mediating the decomposition of above- and below-ground bamboo organs has not been fully explored. In this study, we evaluated the effect of soil fauna in litter decomposition involving five Moso bamboo organs under two different mesh sizes controlling for the accessibility of soil meso- and macrofauna. After 180 days of decomposition, leaf litter accounted for the highest mass loss, followed by the root system (rhizome and fine root), branch and culm litter. Initial chemical traits of organs, especially nitrogen concentration, were strongly related to litter decomposability. Overall, the contribution of soil fauna to mass loss and nutrient loss was not significant at this stage. A survey of the soil fauna communities showed a high differentiation of fauna richness and abundance among the organs. Acari dominated the density of litter fauna with Prostigmata and Oribatida being the dominant suborders. These results show that the contribution of soil fauna is not always straightforward in early phases of decomposition, suggesting that potential interactions between bamboo organs and the fauna community may be dependent on time.