A study was conducted in the field to investigate the interspecific interaction of below-ground and above-ground indices in mulberry-soybean intercropping system. The results showed that above-ground biomass, net photosynthetic rate in leaves, nitrogen content, root dry weight, root length density and nitrate reductase activity in leaves of intercropped mulberry increased 65.9%, 11.8%, 17.8%, 24.8%, 139.8% and 116.2% respectively compared to sole mulberry during the co-growth stage in mulberry/soybean intercropping system, but reduced in intercropped soybean, which indicated the interspecies competition between component crops. Soil microbial biomass C and dehydrogenase activity increased in intercropped soybean compared to sole soybean, which indicated the interspecies facilitation between component crops. It suggested that the coexistence of the interspecific competition and interspecific facilitation in mulberry/soybean intercropping system.