Abstract:Carex trongii K. K. Nguyen (Cyperaceae) is reported as a newly recorded species from Guangxi, China. It grows under the forest in the limestone hills at 900-1000 m. It resembles the plants in Carex sect. Siderostictae Ohwi, but differs by its central culms and densely hispid perigynia. Further study on its position is necessary. The description and illustration of Carex trongii K. K. Nguyen are provided.