Abstract: To examine the contribution of mycorrhizal networks to plant water uptake in karst areas, Cyclobalanopsis glauca seedlings, the main afforestation species in karst areas, were inoculated with mixed Funneliformis mosseae and Rhizophagus intraradices. A root compartmentalization system was used to control the connection between C. glauca seedlings, with adjacent plantsbeing connected only through mycorrhizal networks. Stable hydrogen isotope abundance was used to trace water transport between the mycorrhizal networks and C. glauca seedlings. Our results showed that the density of mycelium decreased with increasing distance from plant roots; the mycelium around C. glauca roots could be found even at a distance of 10-15 cm. There was a significantly positive correlation between hydrogen isotope abundance and mycelial density in the rhizosphere soil. During drought stage, C. glauca seedlings absorbed water via hydraulic lift, with water being transported between adjacent seedlings through the mycorrhizal networks. The contribution of mycorrhizal networks to water transport was estimated using a mixed linear model. The results showed that 1.7%-2.2% of water in the receptor chamber of seedlings was absorbed from the soil of donor chamber by the mycorrhizal networks. The results indicated that water transport by mycorrhizal networks is important for plants with shallow roots in the karst area during the dry season.